literature review for case studies

Get science-backed answers as you write with Paperpal's Research feature

What is a Literature Review? How to Write It (with Examples)

A literature review is a critical analysis and synthesis of existing research on a particular topic. It provides an overview of the current state of knowledge, identifies gaps, and highlights key findings in the literature. 1 The purpose of a literature review is to situate your own research within the context of existing scholarship, demonstrating your understanding of the topic and showing how your work contributes to the ongoing conversation in the field. Learning how to write a literature review is a critical tool for successful research. Your ability to summarize and synthesize prior research pertaining to a certain topic demonstrates your grasp on the topic of study, and assists in the learning process. 

Table of Contents

• What is the purpose of literature review? 
• a. Habitat Loss and Species Extinction: 
• b. Range Shifts and Phenological Changes: 
• c. Ocean Acidification and Coral Reefs: 
• d. Adaptive Strategies and Conservation Efforts: 
• How to write a good literature review 
• Choose a Topic and Define the Research Question: 
• Decide on the Scope of Your Review: 
• Select Databases for Searches: 
• Conduct Searches and Keep Track: 
• Review the Literature: 
• Organize and Write Your Literature Review: 
• Frequently asked questions 

What is a literature review?

A well-conducted literature review demonstrates the researcher’s familiarity with the existing literature, establishes the context for their own research, and contributes to scholarly conversations on the topic. One of the purposes of a literature review is also to help researchers avoid duplicating previous work and ensure that their research is informed by and builds upon the existing body of knowledge.

What is the purpose of literature review?

A literature review serves several important purposes within academic and research contexts. Here are some key objectives and functions of a literature review: 2  

• Contextualizing the Research Problem: The literature review provides a background and context for the research problem under investigation. It helps to situate the study within the existing body of knowledge. 
• Identifying Gaps in Knowledge: By identifying gaps, contradictions, or areas requiring further research, the researcher can shape the research question and justify the significance of the study. This is crucial for ensuring that the new research contributes something novel to the field. 
• Understanding Theoretical and Conceptual Frameworks: Literature reviews help researchers gain an understanding of the theoretical and conceptual frameworks used in previous studies. This aids in the development of a theoretical framework for the current research. 
• Providing Methodological Insights: Another purpose of literature reviews is that it allows researchers to learn about the methodologies employed in previous studies. This can help in choosing appropriate research methods for the current study and avoiding pitfalls that others may have encountered. 
• Establishing Credibility: A well-conducted literature review demonstrates the researcher’s familiarity with existing scholarship, establishing their credibility and expertise in the field. It also helps in building a solid foundation for the new research. 
• Informing Hypotheses or Research Questions: The literature review guides the formulation of hypotheses or research questions by highlighting relevant findings and areas of uncertainty in existing literature. 

Literature review example

Let’s delve deeper with a literature review example: Let’s say your literature review is about the impact of climate change on biodiversity. You might format your literature review into sections such as the effects of climate change on habitat loss and species extinction, phenological changes, and marine biodiversity. Each section would then summarize and analyze relevant studies in those areas, highlighting key findings and identifying gaps in the research. The review would conclude by emphasizing the need for further research on specific aspects of the relationship between climate change and biodiversity. The following literature review template provides a glimpse into the recommended literature review structure and content, demonstrating how research findings are organized around specific themes within a broader topic. 

Literature Review on Climate Change Impacts on Biodiversity:

Climate change is a global phenomenon with far-reaching consequences, including significant impacts on biodiversity. This literature review synthesizes key findings from various studies: 

a. Habitat Loss and Species Extinction:

Climate change-induced alterations in temperature and precipitation patterns contribute to habitat loss, affecting numerous species (Thomas et al., 2004). The review discusses how these changes increase the risk of extinction, particularly for species with specific habitat requirements. 

b. Range Shifts and Phenological Changes:

Observations of range shifts and changes in the timing of biological events (phenology) are documented in response to changing climatic conditions (Parmesan & Yohe, 2003). These shifts affect ecosystems and may lead to mismatches between species and their resources. 

c. Ocean Acidification and Coral Reefs:

The review explores the impact of climate change on marine biodiversity, emphasizing ocean acidification’s threat to coral reefs (Hoegh-Guldberg et al., 2007). Changes in pH levels negatively affect coral calcification, disrupting the delicate balance of marine ecosystems. 

d. Adaptive Strategies and Conservation Efforts:

Recognizing the urgency of the situation, the literature review discusses various adaptive strategies adopted by species and conservation efforts aimed at mitigating the impacts of climate change on biodiversity (Hannah et al., 2007). It emphasizes the importance of interdisciplinary approaches for effective conservation planning. 

How to write a good literature review

Writing a literature review involves summarizing and synthesizing existing research on a particular topic. A good literature review format should include the following elements. 

Introduction: The introduction sets the stage for your literature review, providing context and introducing the main focus of your review. 

• Opening Statement: Begin with a general statement about the broader topic and its significance in the field. 
• Scope and Purpose: Clearly define the scope of your literature review. Explain the specific research question or objective you aim to address. 
• Organizational Framework: Briefly outline the structure of your literature review, indicating how you will categorize and discuss the existing research. 
• Significance of the Study: Highlight why your literature review is important and how it contributes to the understanding of the chosen topic. 
• Thesis Statement: Conclude the introduction with a concise thesis statement that outlines the main argument or perspective you will develop in the body of the literature review. 

Body: The body of the literature review is where you provide a comprehensive analysis of existing literature, grouping studies based on themes, methodologies, or other relevant criteria. 

• Organize by Theme or Concept: Group studies that share common themes, concepts, or methodologies. Discuss each theme or concept in detail, summarizing key findings and identifying gaps or areas of disagreement. 
• Critical Analysis: Evaluate the strengths and weaknesses of each study. Discuss the methodologies used, the quality of evidence, and the overall contribution of each work to the understanding of the topic. 
• Synthesis of Findings: Synthesize the information from different studies to highlight trends, patterns, or areas of consensus in the literature. 
• Identification of Gaps: Discuss any gaps or limitations in the existing research and explain how your review contributes to filling these gaps. 
• Transition between Sections: Provide smooth transitions between different themes or concepts to maintain the flow of your literature review. 

Conclusion: The conclusion of your literature review should summarize the main findings, highlight the contributions of the review, and suggest avenues for future research. 

• Summary of Key Findings: Recap the main findings from the literature and restate how they contribute to your research question or objective. 
• Contributions to the Field: Discuss the overall contribution of your literature review to the existing knowledge in the field. 
• Implications and Applications: Explore the practical implications of the findings and suggest how they might impact future research or practice. 
• Recommendations for Future Research: Identify areas that require further investigation and propose potential directions for future research in the field. 
• Final Thoughts: Conclude with a final reflection on the importance of your literature review and its relevance to the broader academic community. 

Conducting a literature review

Conducting a literature review is an essential step in research that involves reviewing and analyzing existing literature on a specific topic. It’s important to know how to do a literature review effectively, so here are the steps to follow: 1  

Choose a Topic and Define the Research Question:

• Select a topic that is relevant to your field of study. 
• Clearly define your research question or objective. Determine what specific aspect of the topic do you want to explore? 

Decide on the Scope of Your Review:

• Determine the timeframe for your literature review. Are you focusing on recent developments, or do you want a historical overview? 
• Consider the geographical scope. Is your review global, or are you focusing on a specific region? 
• Define the inclusion and exclusion criteria. What types of sources will you include? Are there specific types of studies or publications you will exclude? 

Select Databases for Searches:

• Identify relevant databases for your field. Examples include PubMed, IEEE Xplore, Scopus, Web of Science, and Google Scholar. 
• Consider searching in library catalogs, institutional repositories, and specialized databases related to your topic. 

Conduct Searches and Keep Track:

• Develop a systematic search strategy using keywords, Boolean operators (AND, OR, NOT), and other search techniques. 
• Record and document your search strategy for transparency and replicability. 
• Keep track of the articles, including publication details, abstracts, and links. Use citation management tools like EndNote, Zotero, or Mendeley to organize your references. 

Review the Literature:

• Evaluate the relevance and quality of each source. Consider the methodology, sample size, and results of studies. 
• Organize the literature by themes or key concepts. Identify patterns, trends, and gaps in the existing research. 
• Summarize key findings and arguments from each source. Compare and contrast different perspectives. 
• Identify areas where there is a consensus in the literature and where there are conflicting opinions. 
• Provide critical analysis and synthesis of the literature. What are the strengths and weaknesses of existing research? 

Organize and Write Your Literature Review:

• Literature review outline should be based on themes, chronological order, or methodological approaches. 
• Write a clear and coherent narrative that synthesizes the information gathered. 
• Use proper citations for each source and ensure consistency in your citation style (APA, MLA, Chicago, etc.). 
• Conclude your literature review by summarizing key findings, identifying gaps, and suggesting areas for future research. 

The literature review sample and detailed advice on writing and conducting a review will help you produce a well-structured report. But remember that a literature review is an ongoing process, and it may be necessary to revisit and update it as your research progresses. 

Frequently asked questions

A literature review is a critical and comprehensive analysis of existing literature (published and unpublished works) on a specific topic or research question and provides a synthesis of the current state of knowledge in a particular field. A well-conducted literature review is crucial for researchers to build upon existing knowledge, avoid duplication of efforts, and contribute to the advancement of their field. It also helps researchers situate their work within a broader context and facilitates the development of a sound theoretical and conceptual framework for their studies.

Literature review is a crucial component of research writing, providing a solid background for a research paper’s investigation. The aim is to keep professionals up to date by providing an understanding of ongoing developments within a specific field, including research methods, and experimental techniques used in that field, and present that knowledge in the form of a written report. Also, the depth and breadth of the literature review emphasizes the credibility of the scholar in his or her field.  

Before writing a literature review, it’s essential to undertake several preparatory steps to ensure that your review is well-researched, organized, and focused. This includes choosing a topic of general interest to you and doing exploratory research on that topic, writing an annotated bibliography, and noting major points, especially those that relate to the position you have taken on the topic. 

Literature reviews and academic research papers are essential components of scholarly work but serve different purposes within the academic realm. 3 A literature review aims to provide a foundation for understanding the current state of research on a particular topic, identify gaps or controversies, and lay the groundwork for future research. Therefore, it draws heavily from existing academic sources, including books, journal articles, and other scholarly publications. In contrast, an academic research paper aims to present new knowledge, contribute to the academic discourse, and advance the understanding of a specific research question. Therefore, it involves a mix of existing literature (in the introduction and literature review sections) and original data or findings obtained through research methods. 

Literature reviews are essential components of academic and research papers, and various strategies can be employed to conduct them effectively. If you want to know how to write a literature review for a research paper, here are four common approaches that are often used by researchers.  Chronological Review: This strategy involves organizing the literature based on the chronological order of publication. It helps to trace the development of a topic over time, showing how ideas, theories, and research have evolved.  Thematic Review: Thematic reviews focus on identifying and analyzing themes or topics that cut across different studies. Instead of organizing the literature chronologically, it is grouped by key themes or concepts, allowing for a comprehensive exploration of various aspects of the topic.  Methodological Review: This strategy involves organizing the literature based on the research methods employed in different studies. It helps to highlight the strengths and weaknesses of various methodologies and allows the reader to evaluate the reliability and validity of the research findings.  Theoretical Review: A theoretical review examines the literature based on the theoretical frameworks used in different studies. This approach helps to identify the key theories that have been applied to the topic and assess their contributions to the understanding of the subject.  It’s important to note that these strategies are not mutually exclusive, and a literature review may combine elements of more than one approach. The choice of strategy depends on the research question, the nature of the literature available, and the goals of the review. Additionally, other strategies, such as integrative reviews or systematic reviews, may be employed depending on the specific requirements of the research.

The literature review format can vary depending on the specific publication guidelines. However, there are some common elements and structures that are often followed. Here is a general guideline for the format of a literature review:  Introduction:   Provide an overview of the topic.  Define the scope and purpose of the literature review.  State the research question or objective.  Body:   Organize the literature by themes, concepts, or chronology.  Critically analyze and evaluate each source.  Discuss the strengths and weaknesses of the studies.  Highlight any methodological limitations or biases.  Identify patterns, connections, or contradictions in the existing research.  Conclusion:   Summarize the key points discussed in the literature review.  Highlight the research gap.  Address the research question or objective stated in the introduction.  Highlight the contributions of the review and suggest directions for future research.

Both annotated bibliographies and literature reviews involve the examination of scholarly sources. While annotated bibliographies focus on individual sources with brief annotations, literature reviews provide a more in-depth, integrated, and comprehensive analysis of existing literature on a specific topic. The key differences are as follows: 

References 

• Denney, A. S., & Tewksbury, R. (2013). How to write a literature review.  Journal of criminal justice education ,  24 (2), 218-234. 
• Pan, M. L. (2016).  Preparing literature reviews: Qualitative and quantitative approaches . Taylor & Francis. 
• Cantero, C. (2019). How to write a literature review.  San José State University Writing Center . 

Paperpal is an AI writing assistant that help academics write better, faster with real-time suggestions for in-depth language and grammar correction. Trained on millions of research manuscripts enhanced by professional academic editors, Paperpal delivers human precision at machine speed.  

Try it for free or upgrade to  Paperpal Prime , which unlocks unlimited access to premium features like academic translation, paraphrasing, contextual synonyms, consistency checks and more. It’s like always having a professional academic editor by your side! Go beyond limitations and experience the future of academic writing.  Get Paperpal Prime now at just US$19 a month!

Related Reads:

• Empirical Research: A Comprehensive Guide for Academics 
• How to Write a Scientific Paper in 10 Steps 
• Life Sciences Papers: 9 Tips for Authors Writing in Biological Sciences
• What is an Argumentative Essay? How to Write It (With Examples)

6 Tips for Post-Doc Researchers to Take Their Career to the Next Level

Self-plagiarism in research: what it is and how to avoid it, you may also like, how paperpal’s research feature helps you develop and..., how paperpal is enhancing academic productivity and accelerating..., how to write a successful book chapter for..., academic editing: how to self-edit academic text with..., 4 ways paperpal encourages responsible writing with ai, what are scholarly sources and where can you..., how to write a hypothesis types and examples , measuring academic success: definition & strategies for excellence, what is academic writing: tips for students, why traditional editorial process needs an upgrade.

Organizing Your Social Sciences Research Paper: Writing a Case Study

• Purpose of Guide
• Design Flaws to Avoid
• Independent and Dependent Variables
• Glossary of Research Terms
• Narrowing a Topic Idea
• Broadening a Topic Idea
• Extending the Timeliness of a Topic Idea
• Academic Writing Style
• Choosing a Title
• Making an Outline
• Paragraph Development
• Executive Summary
• The C.A.R.S. Model
• Background Information
• The Research Problem/Question
• Theoretical Framework
• Citation Tracking
• Content Alert Services
• Evaluating Sources
• Reading Research Effectively
• Primary Sources
• Secondary Sources
• Tiertiary Sources
• What Is Scholarly vs. Popular?
• Qualitative Methods
• Quantitative Methods
• Using Non-Textual Elements
• Limitations of the Study
• Common Grammar Mistakes
• Writing Concisely
• Avoiding Plagiarism
• Footnotes or Endnotes?
• Further Readings
• Annotated Bibliography
• Dealing with Nervousness
• Using Visual Aids
• Grading Someone Else's Paper
• Types of Structured Group Activities
• Group Project Survival Skills
• Multiple Book Review Essay
• Reviewing Collected Essays
• Writing a Case Study
• About Informed Consent
• Writing Field Notes
• Writing a Policy Memo
• Writing a Research Proposal
• Bibliography

The term case study refers to both a method of analysis and a specific research design for examining a problem, both of which are used in most circumstances to generalize across populations. This tab focuses on the latter--how to design and organize a research paper in the social sciences that analyzes a specific case.

A case study research paper examines a person, place, event, phenomenon, or other type of subject of analysis in order to extrapolate  key themes and results that help predict future trends, illuminate previously hidden issues that can be applied to practice, and/or provide a means for understanding an important research problem with greater clarity. A case study paper usually examines a single subject of analysis, but case study papers can also be designed as a comparative investigation that shows relationships between two or among more than two subjects. The methods used to study a case can rest within a quantitative, qualitative, or mixed-method investigative paradigm.

Case Studies . Writing@CSU. Colorado State University; Mills, Albert J. , Gabrielle Durepos, and Eiden Wiebe, editors. Encyclopedia of Case Study Research . Thousand Oaks, CA: SAGE Publications, 2010 ; “What is a Case Study?” In Swanborn, Peter G. Case Study Research: What, Why and How? London: SAGE, 2010.

How to Approach Writing a Case Study Research Paper

General information about how to choose a topic to investigate can be found under the " Choosing a Research Problem " tab in this writing guide. Review this page because it may help you identify a subject of analysis that can be investigated using a single case study design.

However, identifying a case to investigate involves more than choosing the research problem . A case study encompasses a problem contextualized around the application of in-depth analysis, interpretation, and discussion, often resulting in specific recommendations for action or for improving existing conditions. As Seawright and Gerring note, practical considerations such as time and access to information can influence case selection, but these issues should not be the sole factors used in describing the methodological justification for identifying a particular case to study. Given this, selecting a case includes considering the following:

• Does the case represent an unusual or atypical example of a research problem that requires more in-depth analysis? Cases often represent a topic that rests on the fringes of prior investigations because the case may provide new ways of understanding the research problem. For example, if the research problem is to identify strategies to improve policies that support girl's access to secondary education in predominantly Muslim nations, you could consider using Azerbaijan as a case study rather than selecting a more obvious nation in the Middle East. Doing so may reveal important new insights into recommending how governments in other predominantly Muslim nations can formulate policies that support improved access to education for girls.
• Does the case provide important insight or illuminate a previously hidden problem? In-depth analysis of a case can be based on the hypothesis that the case study will reveal trends or issues that have not been exposed in prior research or will reveal new and important implications for practice. For example, anecdotal evidence may suggest drug use among homeless veterans is related to their patterns of travel throughout the day. Assuming prior studies have not looked at individual travel choices as a way to study access to illicit drug use, a case study that observes a homeless veteran could reveal how issues of personal mobility choices facilitate regular access to illicit drugs. Note that it is important to conduct a thorough literature review to ensure that your assumption about the need to reveal new insights or previously hidden problems is valid and evidence-based.
• Does the case challenge and offer a counter-point to prevailing assumptions? Over time, research on any given topic can fall into a trap of developing assumptions based on outdated studies that are still applied to new or changing conditions or the idea that something should simply be accepted as "common sense," even though the issue has not been thoroughly tested in practice. A case may offer you an opportunity to gather evidence that challenges prevailing assumptions about a research problem and provide a new set of recommendations applied to practice that have not been tested previously. For example, perhaps there has been a long practice among scholars to apply a particular theory in explaining the relationship between two subjects of analysis. Your case could challenge this assumption by applying an innovative theoretical framework [perhaps borrowed from another discipline] to the study a case in order to explore whether this approach offers new ways of understanding the research problem. Taking a contrarian stance is one of the most important ways that new knowledge and understanding develops from existing literature.
• Does the case provide an opportunity to pursue action leading to the resolution of a problem? Another way to think about choosing a case to study is to consider how the results from investigating a particular case may result in findings that reveal ways in which to resolve an existing or emerging problem. For example, studying the case of an unforeseen incident, such as a fatal accident at a railroad crossing, can reveal hidden issues that could be applied to preventative measures that contribute to reducing the chance of accidents in the future. In this example, a case study investigating the accident could lead to a better understanding of where to strategically locate additional signals at other railroad crossings in order to better warn drivers of an approaching train, particularly when visibility is hindered by heavy rain, fog, or at night.
• Does the case offer a new direction in future research? A case study can be used as a tool for exploratory research that points to a need for further examination of the research problem. A case can be used when there are few studies that help predict an outcome or that establish a clear understanding about how best to proceed in addressing a problem. For example, after conducting a thorough literature review [very important!], you discover that little research exists showing the ways in which women contribute to promoting water conservation in rural communities of Uganda. A case study of how women contribute to saving water in a particular village can lay the foundation for understanding the need for more thorough research that documents how women in their roles as cooks and family caregivers think about water as a valuable resource within their community throughout rural regions of east Africa. The case could also point to the need for scholars to apply feminist theories of work and family to the issue of water conservation.

Eisenhardt, Kathleen M. “Building Theories from Case Study Research.” Academy of Management Review 14 (October 1989): 532-550; Emmel, Nick. Sampling and Choosing Cases in Qualitative Research: A Realist Approach . Thousand Oaks, CA: SAGE Publications, 2013; Gerring, John. “What Is a Case Study and What Is It Good for?” American Political Science Review 98 (May 2004): 341-354; Mills, Albert J. , Gabrielle Durepos, and Eiden Wiebe, editors. Encyclopedia of Case Study Research . Thousand Oaks, CA: SAGE Publications, 2010; Seawright, Jason and John Gerring. "Case Selection Techniques in Case Study Research." Political Research Quarterly 61 (June 2008): 294-308.

Structure and Writing Style

The purpose of a paper in the social sciences designed around a case study is to thoroughly investigate a subject of analysis in order to reveal a new understanding about the research problem and, in so doing, contributing new knowledge to what is already known from previous studies. In applied social sciences disciplines [e.g., education, social work, public administration, etc.], case studies may also be used to reveal best practices, highlight key programs, or investigate interesting aspects of professional work. In general, the structure of a case study research paper is not all that different from a standard college-level research paper. However, there are subtle differences you should be aware of. Here are the key elements to organizing and writing a case study research paper.

I.  Introduction

As with any research paper, your introduction should serve as a roadmap for your readers to ascertain the scope and purpose of your study . The introduction to a case study research paper, however, should not only describe the research problem and its significance, but you should also succinctly describe why the case is being used and how it relates to addressing the problem. The two elements should be linked. With this in mind, a good introduction answers these four questions:

• What was I studying? Describe the research problem and describe the subject of analysis you have chosen to address the problem. Explain how they are linked and what elements of the case will help to expand knowledge and understanding about the problem.
• Why was this topic important to investigate? Describe the significance of the research problem and state why a case study design and the subject of analysis that the paper is designed around is appropriate in addressing the problem.
• What did we know about this topic before I did this study? Provide background that helps lead the reader into the more in-depth literature review to follow. If applicable, summarize prior case study research applied to the research problem and why it fails to adequately address the research problem. Describe why your case will be useful. If no prior case studies have been used to address the research problem, explain why you have selected this subject of analysis.
• How will this study advance new knowledge or new ways of understanding? Explain why your case study will be suitable in helping to expand knowledge and understanding about the research problem.

Each of these questions should be addressed in no more than a few paragraphs. Exceptions to this can be when you are addressing a complex research problem or subject of analysis that requires more in-depth background information.

II.  Literature Review

The literature review for a case study research paper is generally structured the same as it is for any college-level research paper. The difference, however, is that the literature review is focused on providing background information and  enabling historical interpretation of the subject of analysis in relation to the research problem the case is intended to address . This includes synthesizing studies that help to:

• Place relevant works in the context of their contribution to understanding the case study being investigated . This would include summarizing studies that have used a similar subject of analysis to investigate the research problem. If there is literature using the same or a very similar case to study, you need to explain why duplicating past research is important [e.g., conditions have changed; prior studies were conducted long ago, etc.].
• Describe the relationship each work has to the others under consideration that informs the reader why this case is applicable . Your literature review should include a description of any works that support using the case to study the research problem and the underlying research questions.
• Identify new ways to interpret prior research using the case study . If applicable, review any research that has examined the research problem using a different research design. Explain how your case study design may reveal new knowledge or a new perspective or that can redirect research in an important new direction.
• Resolve conflicts amongst seemingly contradictory previous studies . This refers to synthesizing any literature that points to unresolved issues of concern about the research problem and describing how the subject of analysis that forms the case study can help resolve these existing contradictions.
• Point the way in fulfilling a need for additional research . Your review should examine any literature that lays a foundation for understanding why your case study design and the subject of analysis around which you have designed your study may reveal a new way of approaching the research problem or offer a perspective that points to the need for additional research.
• Expose any gaps that exist in the literature that the case study could help to fill . Summarize any literature that not only shows how your subject of analysis contributes to understanding the research problem, but how your case contributes to a new way of understanding the problem that prior research has failed to do.
• Locate your own research within the context of existing literature [very important!] . Collectively, your literature review should always place your case study within the larger domain of prior research about the problem. The overarching purpose of reviewing pertinent literature in a case study paper is to demonstrate that you have thoroughly identified and synthesized prior studies in the context of explaining the relevance of the case in addressing the research problem.

III.  Method

In this section, you explain why you selected a particular subject of analysis to study and the strategy you used to identify and ultimately decide that your case was appropriate in addressing the research problem. The way you describe the methods used varies depending on the type of subject of analysis that frames your case study.

If your subject of analysis is an incident or event . In the social and behavioral sciences, the event or incident that represents the case to be studied is usually bounded by time and place, with a clear beginning and end and with an identifiable location or position relative to its surroundings. The subject of analysis can be a rare or critical event or it can focus on a typical or regular event. The purpose of studying a rare event is to illuminate new ways of thinking about the broader research problem or to test a hypothesis. Critical incident case studies must describe the method by which you identified the event and explain the process by which you determined the validity of this case to inform broader perspectives about the research problem or to reveal new findings. However, the event does not have to be a rare or uniquely significant to support new thinking about the research problem or to challenge an existing hypothesis. For example, Walo, Bull, and Breen conducted a case study to identify and evaluate the direct and indirect economic benefits and costs of a local sports event in the City of Lismore, New South Wales, Australia. The purpose of their study was to provide new insights from measuring the impact of a typical local sports event that prior studies could not measure well because they focused on large "mega-events." Whether the event is rare or not, the methods section should include an explanation of the following characteristics of the event: a) when did it take place; b) what were the underlying circumstances leading to the event; c) what were the consequences of the event.

If your subject of analysis is a person. Explain why you selected this particular individual to be studied and describe what experience he or she has had that provides an opportunity to advance new understandings about the research problem. Mention any background about this person which might help the reader understand the significance of his/her experiences that make them worthy of study. This includes describing the relationships this person has had with other people, institutions, and/or events that support using him or her as the subject for a case study research paper. It is particularly important to differentiate the person as the subject of analysis from others and to succinctly explain how the person relates to examining the research problem.

If your subject of analysis is a place. In general, a case study that investigates a place suggests a subject of analysis that is unique or special in some way and that this uniqueness can be used to build new understanding or knowledge about the research problem. A case study of a place must not only describe its various attributes relevant to the research problem [e.g., physical, social, cultural, economic, political, etc.], but you must state the method by which you determined that this place will illuminate new understandings about the research problem. It is also important to articulate why a particular place as the case for study is being used if similar places also exist [i.e., if you are studying patterns of homeless encampments of veterans in open spaces, why study Echo Park in Los Angeles rather than Griffith Park?]. If applicable, describe what type of human activity involving this place makes it a good choice to study [e.g., prior research reveals Echo Park has more homeless veterans].

If your subject of analysis is a phenomenon. A phenomenon refers to a fact, occurrence, or circumstance that can be studied or observed but with the cause or explanation to be in question. In this sense, a phenomenon that forms your subject of analysis can encompass anything that can be observed or presumed to exist but is not fully understood. In the social and behavioral sciences, the case usually focuses on human interaction within a complex physical, social, economic, cultural, or political system. For example, the phenomenon could be the observation that many vehicles used by ISIS fighters are small trucks with English language advertisements on them. The research problem could be that ISIS fighters are difficult to combat because they are highly mobile. The research questions could be how and by what means are these vehicles used by ISIS being supplied to the militants and how might supply lines to these vehicles be cut? How might knowing the suppliers of these trucks from overseas reveal larger networks of collaborators and financial support? A case study of a phenomenon most often encompasses an in-depth analysis of a cause and effect that is grounded in an interactive relationship between people and their environment in some way.

NOTE:   The choice of the case or set of cases to study cannot appear random. Evidence that supports the method by which you identified and chose your subject of analysis should be linked to the findings from the literature review. Be sure to cite any prior studies that helped you determine that the case you chose was appropriate for investigating the research problem.

IV.  Discussion

The main elements of your discussion section are generally the same as any research paper, but centered around interpreting and drawing conclusions about the key findings from your case study. Note that a general social sciences research paper may contain a separate section to report findings. However, in a paper designed around a case study, it is more common to combine a description of the findings with the discussion about their implications. The objectives of your discussion section should include the following:

Reiterate the Research Problem/State the Major Findings Briefly reiterate the research problem you are investigating and explain why the subject of analysis around which you designed the case study were used. You should then describe the findings revealed from your study of the case using direct, declarative, and succinct proclamation of the study results. Highlight any findings that were unexpected or especially profound.

Explain the Meaning of the Findings and Why They are Important Systematically explain the meaning of your case study findings and why you believe they are important. Begin this part of the section by repeating what you consider to be your most important or surprising finding first, then systematically review each finding. Be sure to thoroughly extrapolate what your analysis of the case can tell the reader about situations or conditions beyond the actual case that was studied while, at the same time, being careful not to misconstrue or conflate a finding that undermines the external validity of your conclusions.

Relate the Findings to Similar Studies No study in the social sciences is so novel or possesses such a restricted focus that it has absolutely no relation to previously published research. The discussion section should relate your case study results to those found in other studies, particularly if questions raised from prior studies served as the motivation for choosing your subject of analysis. This is important because comparing and contrasting the findings of other studies helps to support the overall importance of your results and it highlights how and in what ways your case study design and the subject of analysis differs from prior research about the topic.

Consider Alternative Explanations of the Findings It is important to remember that the purpose of social science research is to discover and not to prove. When writing the discussion section, you should carefully consider all possible explanations for the case study results, rather than just those that fit your hypothesis or prior assumptions and biases. Be alert to what the in-depth analysis of the case may reveal about the research problem, including offering a contrarian perspective to what scholars have stated in prior research.

Acknowledge the Study's Limitations You can state the study's limitations in the conclusion section of your paper but describing the limitations of your subject of analysis in the discussion section provides an opportunity to identify the limitations and explain why they are not significant. This part of the discussion section should also note any unanswered questions or issues your case study could not address. More detailed information about how to document any limitations to your research can be found here .

Suggest Areas for Further Research Although your case study may offer important insights about the research problem, there are likely additional questions related to the problem that remain unanswered or findings that unexpectedly revealed themselves as a result of your in-depth analysis of the case. Be sure that the recommendations for further research are linked to the research problem and that you explain why your recommendations are valid in other contexts and based on the original assumptions of your study.

V.  Conclusion

As with any research paper, you should summarize your conclusion in clear, simple language; emphasize how the findings from your case study differs from or supports prior research and why. Do not simply reiterate the discussion section. Provide a synthesis of key findings presented in the paper to show how these converge to address the research problem. If you haven't already done so in the discussion section, be sure to document the limitations of your case study and needs for further research.

The function of your paper's conclusion is to: 1)  restate the main argument supported by the findings from the analysis of your case; 2) clearly state the context, background, and necessity of pursuing the research problem using a case study design in relation to an issue, controversy, or a gap found from reviewing the literature; and, 3) provide a place for you to persuasively and succinctly restate the significance of your research problem, given that the reader has now been presented with in-depth information about the topic.

Consider the following points to help ensure your conclusion is appropriate:

• If the argument or purpose of your paper is complex, you may need to summarize these points for your reader.
• If prior to your conclusion, you have not yet explained the significance of your findings or if you are proceeding inductively, use the conclusion of your paper to describe your main points and explain their significance.
• Move from a detailed to a general level of consideration of the case study's findings that returns the topic to the context provided by the introduction or within a new context that emerges from your case study findings.

Note that, depending on the discipline you are writing in and your professor's preferences, the concluding paragraph may contain your final reflections on the evidence presented applied to practice or on the essay's central research problem. However, the nature of being introspective about the subject of analysis you have investigated will depend on whether you are explicitly asked to express your observations in this way.

Problems to Avoid

Overgeneralization One of the goals of a case study is to lay a foundation for understanding broader trends and issues applied to similar circumstances. However, be careful when drawing conclusions from your case study. They must be evidence-based and grounded in the results of the study; otherwise, it is merely speculation. Looking at a prior example, it would be incorrect to state that a factor in improving girls access to education in Azerbaijan and the policy implications this may have for improving access in other Muslim nations is due to girls access to social media if there is no documentary evidence from your case study to indicate this. There may be anecdotal evidence that retention rates were better for girls who were on social media, but this observation would only point to the need for further research and would not be a definitive finding if this was not a part of your original research agenda.

Failure to Document Limitations No case is going to reveal all that needs to be understood about a research problem. Therefore, just as you have to clearly state the limitations of a general research study , you must describe the specific limitations inherent in the subject of analysis. For example, the case of studying how women conceptualize the need for water conservation in a village in Uganda could have limited application in other cultural contexts or in areas where fresh water from rivers or lakes is plentiful and, therefore, conservation is understood differently than preserving access to a scarce resource.

Failure to Extrapolate All Possible Implications Just as you don't want to over-generalize from your case study findings, you also have to be thorough in the consideration of all possible outcomes or recommendations derived from your findings. If you do not, your reader may question the validity of your analysis, particularly if you failed to document an obvious outcome from your case study research. For example, in the case of studying the accident at the railroad crossing to evaluate where and what types of warning signals should be located, you failed to take into consideration speed limit signage as well as warning signals. When designing your case study, be sure you have thoroughly addressed all aspects of the problem and do not leave gaps in your analysis.

Case Studies . Writing@CSU. Colorado State University; Gerring, John. Case Study Research: Principles and Practices . New York: Cambridge University Press, 2007; Merriam, Sharan B. Qualitative Research and Case Study Applications in Education . Rev. ed. San Francisco, CA: Jossey-Bass, 1998; Miller, Lisa L. “The Use of Case Studies in Law and Social Science Research.” Annual Review of Law and Social Science 14 (2018): TBD; Mills, Albert J., Gabrielle Durepos, and Eiden Wiebe, editors. Encyclopedia of Case Study Research . Thousand Oaks, CA: SAGE Publications, 2010; Putney, LeAnn Grogan. "Case Study." In Encyclopedia of Research Design , Neil J. Salkind, editor. (Thousand Oaks, CA: SAGE Publications, 2010), pp. 116-120; Simons, Helen. Case Study Research in Practice . London: SAGE Publications, 2009;  Kratochwill,  Thomas R. and Joel R. Levin, editors. Single-Case Research Design and Analysis: New Development for Psychology and Education .  Hilldsale, NJ: Lawrence Erlbaum Associates, 1992; Swanborn, Peter G. Case Study Research: What, Why and How? London : SAGE, 2010; Yin, Robert K. Case Study Research: Design and Methods . 6th edition. Los Angeles, CA, SAGE Publications, 2014; Walo, Maree, Adrian Bull, and Helen Breen. “Achieving Economic Benefits at Local Events: A Case Study of a Local Sports Event.” Festival Management and Event Tourism 4 (1996): 95-106.

Writing Tip

At Least Five Misconceptions about Case Study Research

Social science case studies are often perceived as limited in their ability to create new knowledge because they are not randomly selected and findings cannot be generalized to larger populations. Flyvbjerg examines five misunderstandings about case study research and systematically "corrects" each one. To quote, these are:

Misunderstanding 1 :  General, theoretical [context-independent knowledge is more valuable than concrete, practical (context-dependent) knowledge. Misunderstanding 2 :  One cannot generalize on the basis of an individual case; therefore, the case study cannot contribute to scientific development. Misunderstanding 3 :  The case study is most useful for generating hypotheses; that is, in the first stage of a total research process, whereas other methods are more suitable for hypotheses testing and theory building. Misunderstanding 4 :  The case study contains a bias toward verification, that is, a tendency to confirm the researcher’s preconceived notions. Misunderstanding 5 :  It is often difficult to summarize and develop general propositions and theories on the basis of specific case studies [p. 221].

While writing your paper, think introspectively about how you addressed these misconceptions because to do so can help you strengthen the validity and reliability of your research by clarifying issues of case selection, the testing and challenging of existing assumptions, the interpretation of key findings, and the summation of case outcomes. Think of a case study research paper as a complete, in-depth narrative about the specific properties and key characteristics of your subject of analysis applied to the research problem.

Flyvbjerg, Bent. “Five Misunderstandings About Case-Study Research.” Qualitative Inquiry 12 (April 2006): 219-245.

• << Previous: Reviewing Collected Essays
• Next: Writing a Field Report >>
• Last Updated: Jan 17, 2023 10:50 AM
• URL: https://libguides.pointloma.edu/ResearchPaper

Have a language expert improve your writing

Run a free plagiarism check in 10 minutes, automatically generate references for free.

• Knowledge Base
• Dissertation
• What is a Literature Review? | Guide, Template, & Examples

What is a Literature Review? | Guide, Template, & Examples

Published on 22 February 2022 by Shona McCombes . Revised on 7 June 2022.

What is a literature review? A literature review is a survey of scholarly sources on a specific topic. It provides an overview of current knowledge, allowing you to identify relevant theories, methods, and gaps in the existing research.

There are five key steps to writing a literature review:

• Search for relevant literature
• Evaluate sources
• Identify themes, debates and gaps
• Outline the structure
• Write your literature review

A good literature review doesn’t just summarise sources – it analyses, synthesises, and critically evaluates to give a clear picture of the state of knowledge on the subject.

Instantly correct all language mistakes in your text

Be assured that you'll submit flawless writing. Upload your document to correct all your mistakes.

Table of contents

Why write a literature review, examples of literature reviews, step 1: search for relevant literature, step 2: evaluate and select sources, step 3: identify themes, debates and gaps, step 4: outline your literature review’s structure, step 5: write your literature review, frequently asked questions about literature reviews, introduction.

• Quick Run-through
• Step 1 & 2

When you write a dissertation or thesis, you will have to conduct a literature review to situate your research within existing knowledge. The literature review gives you a chance to:

• Demonstrate your familiarity with the topic and scholarly context
• Develop a theoretical framework and methodology for your research
• Position yourself in relation to other researchers and theorists
• Show how your dissertation addresses a gap or contributes to a debate

You might also have to write a literature review as a stand-alone assignment. In this case, the purpose is to evaluate the current state of research and demonstrate your knowledge of scholarly debates around a topic.

The content will look slightly different in each case, but the process of conducting a literature review follows the same steps. We’ve written a step-by-step guide that you can follow below.

The only proofreading tool specialized in correcting academic writing

The academic proofreading tool has been trained on 1000s of academic texts and by native English editors. Making it the most accurate and reliable proofreading tool for students.

Correct my document today

Writing literature reviews can be quite challenging! A good starting point could be to look at some examples, depending on what kind of literature review you’d like to write.

• Example literature review #1: “Why Do People Migrate? A Review of the Theoretical Literature” ( Theoretical literature review about the development of economic migration theory from the 1950s to today.)
• Example literature review #2: “Literature review as a research methodology: An overview and guidelines” ( Methodological literature review about interdisciplinary knowledge acquisition and production.)
• Example literature review #3: “The Use of Technology in English Language Learning: A Literature Review” ( Thematic literature review about the effects of technology on language acquisition.)
• Example literature review #4: “Learners’ Listening Comprehension Difficulties in English Language Learning: A Literature Review” ( Chronological literature review about how the concept of listening skills has changed over time.)

You can also check out our templates with literature review examples and sample outlines at the links below.

Download Word doc Download Google doc

Before you begin searching for literature, you need a clearly defined topic .

If you are writing the literature review section of a dissertation or research paper, you will search for literature related to your research objectives and questions .

If you are writing a literature review as a stand-alone assignment, you will have to choose a focus and develop a central question to direct your search. Unlike a dissertation research question, this question has to be answerable without collecting original data. You should be able to answer it based only on a review of existing publications.

Make a list of keywords

Start by creating a list of keywords related to your research topic. Include each of the key concepts or variables you’re interested in, and list any synonyms and related terms. You can add to this list if you discover new keywords in the process of your literature search.

• Social media, Facebook, Instagram, Twitter, Snapchat, TikTok
• Body image, self-perception, self-esteem, mental health
• Generation Z, teenagers, adolescents, youth

Search for relevant sources

Use your keywords to begin searching for sources. Some databases to search for journals and articles include:

• Your university’s library catalogue
• Google Scholar
• Project Muse (humanities and social sciences)
• Medline (life sciences and biomedicine)
• EconLit (economics)
• Inspec (physics, engineering and computer science)

You can use boolean operators to help narrow down your search:

Read the abstract to find out whether an article is relevant to your question. When you find a useful book or article, you can check the bibliography to find other relevant sources.

To identify the most important publications on your topic, take note of recurring citations. If the same authors, books or articles keep appearing in your reading, make sure to seek them out.

You probably won’t be able to read absolutely everything that has been written on the topic – you’ll have to evaluate which sources are most relevant to your questions.

For each publication, ask yourself:

• What question or problem is the author addressing?
• What are the key concepts and how are they defined?
• What are the key theories, models and methods? Does the research use established frameworks or take an innovative approach?
• What are the results and conclusions of the study?
• How does the publication relate to other literature in the field? Does it confirm, add to, or challenge established knowledge?
• How does the publication contribute to your understanding of the topic? What are its key insights and arguments?
• What are the strengths and weaknesses of the research?

Make sure the sources you use are credible, and make sure you read any landmark studies and major theories in your field of research.

You can find out how many times an article has been cited on Google Scholar – a high citation count means the article has been influential in the field, and should certainly be included in your literature review.

The scope of your review will depend on your topic and discipline: in the sciences you usually only review recent literature, but in the humanities you might take a long historical perspective (for example, to trace how a concept has changed in meaning over time).

Remember that you can use our template to summarise and evaluate sources you’re thinking about using!

Take notes and cite your sources

As you read, you should also begin the writing process. Take notes that you can later incorporate into the text of your literature review.

It’s important to keep track of your sources with references to avoid plagiarism . It can be helpful to make an annotated bibliography, where you compile full reference information and write a paragraph of summary and analysis for each source. This helps you remember what you read and saves time later in the process.

You can use our free APA Reference Generator for quick, correct, consistent citations.

To begin organising your literature review’s argument and structure, you need to understand the connections and relationships between the sources you’ve read. Based on your reading and notes, you can look for:

• Trends and patterns (in theory, method or results): do certain approaches become more or less popular over time?
• Themes: what questions or concepts recur across the literature?
• Debates, conflicts and contradictions: where do sources disagree?
• Pivotal publications: are there any influential theories or studies that changed the direction of the field?
• Gaps: what is missing from the literature? Are there weaknesses that need to be addressed?

This step will help you work out the structure of your literature review and (if applicable) show how your own research will contribute to existing knowledge.

• Most research has focused on young women.
• There is an increasing interest in the visual aspects of social media.
• But there is still a lack of robust research on highly-visual platforms like Instagram and Snapchat – this is a gap that you could address in your own research.

There are various approaches to organising the body of a literature review. You should have a rough idea of your strategy before you start writing.

Depending on the length of your literature review, you can combine several of these strategies (for example, your overall structure might be thematic, but each theme is discussed chronologically).

Chronological

The simplest approach is to trace the development of the topic over time. However, if you choose this strategy, be careful to avoid simply listing and summarising sources in order.

Try to analyse patterns, turning points and key debates that have shaped the direction of the field. Give your interpretation of how and why certain developments occurred.

If you have found some recurring central themes, you can organise your literature review into subsections that address different aspects of the topic.

For example, if you are reviewing literature about inequalities in migrant health outcomes, key themes might include healthcare policy, language barriers, cultural attitudes, legal status, and economic access.

Methodological

If you draw your sources from different disciplines or fields that use a variety of research methods , you might want to compare the results and conclusions that emerge from different approaches. For example:

• Look at what results have emerged in qualitative versus quantitative research
• Discuss how the topic has been approached by empirical versus theoretical scholarship
• Divide the literature into sociological, historical, and cultural sources

Theoretical

A literature review is often the foundation for a theoretical framework . You can use it to discuss various theories, models, and definitions of key concepts.

You might argue for the relevance of a specific theoretical approach, or combine various theoretical concepts to create a framework for your research.

Like any other academic text, your literature review should have an introduction , a main body, and a conclusion . What you include in each depends on the objective of your literature review.

The introduction should clearly establish the focus and purpose of the literature review.

If you are writing the literature review as part of your dissertation or thesis, reiterate your central problem or research question and give a brief summary of the scholarly context. You can emphasise the timeliness of the topic (“many recent studies have focused on the problem of x”) or highlight a gap in the literature (“while there has been much research on x, few researchers have taken y into consideration”).

Depending on the length of your literature review, you might want to divide the body into subsections. You can use a subheading for each theme, time period, or methodological approach.

As you write, make sure to follow these tips:

• Summarise and synthesise: give an overview of the main points of each source and combine them into a coherent whole.
• Analyse and interpret: don’t just paraphrase other researchers – add your own interpretations, discussing the significance of findings in relation to the literature as a whole.
• Critically evaluate: mention the strengths and weaknesses of your sources.
• Write in well-structured paragraphs: use transitions and topic sentences to draw connections, comparisons and contrasts.

In the conclusion, you should summarise the key findings you have taken from the literature and emphasise their significance.

If the literature review is part of your dissertation or thesis, reiterate how your research addresses gaps and contributes new knowledge, or discuss how you have drawn on existing theories and methods to build a framework for your research. This can lead directly into your methodology section.

A literature review is a survey of scholarly sources (such as books, journal articles, and theses) related to a specific topic or research question .

It is often written as part of a dissertation , thesis, research paper , or proposal .

There are several reasons to conduct a literature review at the beginning of a research project:

• To familiarise yourself with the current state of knowledge on your topic
• To ensure that you’re not just repeating what others have already done
• To identify gaps in knowledge and unresolved problems that your research can address
• To develop your theoretical framework and methodology
• To provide an overview of the key findings and debates on the topic

Writing the literature review shows your reader how your work relates to existing research and what new insights it will contribute.

The literature review usually comes near the beginning of your  dissertation . After the introduction , it grounds your research in a scholarly field and leads directly to your theoretical framework or methodology .

Cite this Scribbr article

If you want to cite this source, you can copy and paste the citation or click the ‘Cite this Scribbr article’ button to automatically add the citation to our free Reference Generator.

McCombes, S. (2022, June 07). What is a Literature Review? | Guide, Template, & Examples. Scribbr. Retrieved 6 May 2024, from https://www.scribbr.co.uk/thesis-dissertation/literature-review/

Is this article helpful?

Shona McCombes

Other students also liked, how to write a dissertation proposal | a step-by-step guide, what is a theoretical framework | a step-by-step guide, what is a research methodology | steps & tips.

Harvey Cushing/John Hay Whitney Medical Library

• Collections
• Research Help

YSN Doctoral Programs: Steps in Conducting a Literature Review

• Biomedical Databases
• Global (Public Health) Databases
• Soc. Sci., History, and Law Databases
• Grey Literature
• Trials Registers
• Data and Statistics
• Public Policy
• Google Tips
• Recommended Books
• Steps in Conducting a Literature Review

What is a literature review?

A literature review is an integrated analysis -- not just a summary-- of scholarly writings and other relevant evidence related directly to your research question.  That is, it represents a synthesis of the evidence that provides background information on your topic and shows a association between the evidence and your research question.

A literature review may be a stand alone work or the introduction to a larger research paper, depending on the assignment.  Rely heavily on the guidelines your instructor has given you.

Why is it important?

A literature review is important because it:

• Explains the background of research on a topic.
• Demonstrates why a topic is significant to a subject area.
• Discovers relationships between research studies/ideas.
• Identifies major themes, concepts, and researchers on a topic.
• Identifies critical gaps and points of disagreement.
• Discusses further research questions that logically come out of the previous studies.

APA7 Style resources

APA Style Blog - for those harder to find answers

1. Choose a topic. Define your research question.

Your literature review should be guided by your central research question.  The literature represents background and research developments related to a specific research question, interpreted and analyzed by you in a synthesized way.

• Make sure your research question is not too broad or too narrow.  Is it manageable?
• Begin writing down terms that are related to your question. These will be useful for searches later.
• If you have the opportunity, discuss your topic with your professor and your class mates.

2. Decide on the scope of your review

How many studies do you need to look at? How comprehensive should it be? How many years should it cover? 

• This may depend on your assignment.  How many sources does the assignment require?

3. Select the databases you will use to conduct your searches.

Make a list of the databases you will search. 

Where to find databases:

• use the tabs on this guide
• Find other databases in the Nursing Information Resources web page
• More on the Medical Library web page
• ... and more on the Yale University Library web page

4. Conduct your searches to find the evidence. Keep track of your searches.

• Use the key words in your question, as well as synonyms for those words, as terms in your search. Use the database tutorials for help.
• Save the searches in the databases. This saves time when you want to redo, or modify, the searches. It is also helpful to use as a guide is the searches are not finding any useful results.
• Review the abstracts of research studies carefully. This will save you time.
• Use the bibliographies and references of research studies you find to locate others.
• Check with your professor, or a subject expert in the field, if you are missing any key works in the field.
• Ask your librarian for help at any time.
• Use a citation manager, such as EndNote as the repository for your citations. See the EndNote tutorials for help.

Review the literature

Some questions to help you analyze the research:

• What was the research question of the study you are reviewing? What were the authors trying to discover?
• Was the research funded by a source that could influence the findings?
• What were the research methodologies? Analyze its literature review, the samples and variables used, the results, and the conclusions.
• Does the research seem to be complete? Could it have been conducted more soundly? What further questions does it raise?
• If there are conflicting studies, why do you think that is?
• How are the authors viewed in the field? Has this study been cited? If so, how has it been analyzed?

Tips: 

• Review the abstracts carefully.  
• Keep careful notes so that you may track your thought processes during the research process.
• Create a matrix of the studies for easy analysis, and synthesis, across all of the studies.
• << Previous: Recommended Books
• Last Updated: Jan 4, 2024 10:52 AM
• URL: https://guides.library.yale.edu/YSNDoctoral

Purdue Online Writing Lab Purdue OWL® College of Liberal Arts

Writing a Literature Review

Welcome to the Purdue OWL

This page is brought to you by the OWL at Purdue University. When printing this page, you must include the entire legal notice.

Copyright ©1995-2018 by The Writing Lab & The OWL at Purdue and Purdue University. All rights reserved. This material may not be published, reproduced, broadcast, rewritten, or redistributed without permission. Use of this site constitutes acceptance of our terms and conditions of fair use.

A literature review is a document or section of a document that collects key sources on a topic and discusses those sources in conversation with each other (also called synthesis ). The lit review is an important genre in many disciplines, not just literature (i.e., the study of works of literature such as novels and plays). When we say “literature review” or refer to “the literature,” we are talking about the research ( scholarship ) in a given field. You will often see the terms “the research,” “the scholarship,” and “the literature” used mostly interchangeably.

Where, when, and why would I write a lit review?

There are a number of different situations where you might write a literature review, each with slightly different expectations; different disciplines, too, have field-specific expectations for what a literature review is and does. For instance, in the humanities, authors might include more overt argumentation and interpretation of source material in their literature reviews, whereas in the sciences, authors are more likely to report study designs and results in their literature reviews; these differences reflect these disciplines’ purposes and conventions in scholarship. You should always look at examples from your own discipline and talk to professors or mentors in your field to be sure you understand your discipline’s conventions, for literature reviews as well as for any other genre.

A literature review can be a part of a research paper or scholarly article, usually falling after the introduction and before the research methods sections. In these cases, the lit review just needs to cover scholarship that is important to the issue you are writing about; sometimes it will also cover key sources that informed your research methodology.

Lit reviews can also be standalone pieces, either as assignments in a class or as publications. In a class, a lit review may be assigned to help students familiarize themselves with a topic and with scholarship in their field, get an idea of the other researchers working on the topic they’re interested in, find gaps in existing research in order to propose new projects, and/or develop a theoretical framework and methodology for later research. As a publication, a lit review usually is meant to help make other scholars’ lives easier by collecting and summarizing, synthesizing, and analyzing existing research on a topic. This can be especially helpful for students or scholars getting into a new research area, or for directing an entire community of scholars toward questions that have not yet been answered.

What are the parts of a lit review?

Most lit reviews use a basic introduction-body-conclusion structure; if your lit review is part of a larger paper, the introduction and conclusion pieces may be just a few sentences while you focus most of your attention on the body. If your lit review is a standalone piece, the introduction and conclusion take up more space and give you a place to discuss your goals, research methods, and conclusions separately from where you discuss the literature itself.

Introduction:

• An introductory paragraph that explains what your working topic and thesis is
• A forecast of key topics or texts that will appear in the review
• Potentially, a description of how you found sources and how you analyzed them for inclusion and discussion in the review (more often found in published, standalone literature reviews than in lit review sections in an article or research paper)
• Summarize and synthesize: Give an overview of the main points of each source and combine them into a coherent whole
• Analyze and interpret: Don’t just paraphrase other researchers – add your own interpretations where possible, discussing the significance of findings in relation to the literature as a whole
• Critically Evaluate: Mention the strengths and weaknesses of your sources
• Write in well-structured paragraphs: Use transition words and topic sentence to draw connections, comparisons, and contrasts.

Conclusion:

• Summarize the key findings you have taken from the literature and emphasize their significance
• Connect it back to your primary research question

How should I organize my lit review?

Lit reviews can take many different organizational patterns depending on what you are trying to accomplish with the review. Here are some examples:

• Chronological : The simplest approach is to trace the development of the topic over time, which helps familiarize the audience with the topic (for instance if you are introducing something that is not commonly known in your field). If you choose this strategy, be careful to avoid simply listing and summarizing sources in order. Try to analyze the patterns, turning points, and key debates that have shaped the direction of the field. Give your interpretation of how and why certain developments occurred (as mentioned previously, this may not be appropriate in your discipline — check with a teacher or mentor if you’re unsure).
• Thematic : If you have found some recurring central themes that you will continue working with throughout your piece, you can organize your literature review into subsections that address different aspects of the topic. For example, if you are reviewing literature about women and religion, key themes can include the role of women in churches and the religious attitude towards women.
• Qualitative versus quantitative research
• Empirical versus theoretical scholarship
• Divide the research by sociological, historical, or cultural sources
• Theoretical : In many humanities articles, the literature review is the foundation for the theoretical framework. You can use it to discuss various theories, models, and definitions of key concepts. You can argue for the relevance of a specific theoretical approach or combine various theorical concepts to create a framework for your research.

What are some strategies or tips I can use while writing my lit review?

Any lit review is only as good as the research it discusses; make sure your sources are well-chosen and your research is thorough. Don’t be afraid to do more research if you discover a new thread as you’re writing. More info on the research process is available in our "Conducting Research" resources .

As you’re doing your research, create an annotated bibliography ( see our page on the this type of document ). Much of the information used in an annotated bibliography can be used also in a literature review, so you’ll be not only partially drafting your lit review as you research, but also developing your sense of the larger conversation going on among scholars, professionals, and any other stakeholders in your topic.

Usually you will need to synthesize research rather than just summarizing it. This means drawing connections between sources to create a picture of the scholarly conversation on a topic over time. Many student writers struggle to synthesize because they feel they don’t have anything to add to the scholars they are citing; here are some strategies to help you:

• It often helps to remember that the point of these kinds of syntheses is to show your readers how you understand your research, to help them read the rest of your paper.
• Writing teachers often say synthesis is like hosting a dinner party: imagine all your sources are together in a room, discussing your topic. What are they saying to each other?
• Look at the in-text citations in each paragraph. Are you citing just one source for each paragraph? This usually indicates summary only. When you have multiple sources cited in a paragraph, you are more likely to be synthesizing them (not always, but often
• Read more about synthesis here.

The most interesting literature reviews are often written as arguments (again, as mentioned at the beginning of the page, this is discipline-specific and doesn’t work for all situations). Often, the literature review is where you can establish your research as filling a particular gap or as relevant in a particular way. You have some chance to do this in your introduction in an article, but the literature review section gives a more extended opportunity to establish the conversation in the way you would like your readers to see it. You can choose the intellectual lineage you would like to be part of and whose definitions matter most to your thinking (mostly humanities-specific, but this goes for sciences as well). In addressing these points, you argue for your place in the conversation, which tends to make the lit review more compelling than a simple reporting of other sources.

CC0006 Basics of Report Writing

Structure of a report (case study, literature review or survey).

• Structure of report (Site visit)
• Citing Sources
• Tips and Resources

The information in the report has to be organised in the best possible way for the reader to understand the issue being investigated, analysis of the findings and recommendations or implications that relate directly to the findings. Given below are the main sections of a standard report. Click on each section heading to learn more about it.

• Tells the reader what the report is about
• Informative, short, catchy

Example - Sea level rise in Singapore : Causes, Impact and Solution

The title page must also include group name, group members and their matriculation numbers.

Content s Page

• Has headings and subheadings that show the reader where the various sections of the report are located
• Written on a separate page
• Includes the page numbers of each section
• Briefly summarises the report, the process of research and final conclusions
• Provides a quick overview of the report and describes the main highlights
• Short, usually not more than 150 words in length
• Mention briefly why you choose this project, what are the implications and what kind of problems it will solve

Usually, the abstract is written last, ie. after writing the other sections and you know the key points to draw out from these sections. Abstracts allow readers who may be interested in the report to decide whether it is relevant to their purposes.

Introduction

• Discusses the background and sets the context
• Introduces the topic, significance of the problem, and the purpose of research
• Gives the scope ie shows what it includes and excludes

In the introduction, write about what motivates your project, what makes it interesting, what questions do you aim to answer by doing your project. The introduction lays the foundation for understanding the research problem and should be written in a way that leads the reader from the general subject area of the topic to the particular topic of research.

Literature Review

• Helps to gain an understanding of the existing research in that topic
• To develop on your own ideas and build your ideas based on the existing knowledge
• Prevents duplication of the research done by others

Search the existing literature for information. Identify the data pertinent to your topic. Review, extract the relevant information for eg how the study was conducted and the findings. Summarise the information. Write what is already known about the topic and what do the sources that you have reviewed say. Identify conflicts in previous studies, open questions, or gaps that may exist. If you are doing

• Case study - look for background information and if any similar case studies have been done before.
• Literature review - find out from literature, what is the background to the questions that you are looking into
• Site visit - use the literature review to read up and prepare good questions before hand.
• Survey - find out if similar surveys have been done before and what did they find?

Keep a record of the source details of any information you want to use in your report so that you can reference them accurately.

Methodology

Methodology is the approach that you take to gather data and arrive at the recommendation(s). Choose a method that is appropriate for the research topic and explain it in detail.

In this section, address the following: a) How the data was collected b) How it was analysed and c) Explain or justify why a particular method was chosen.

Usually, the methodology is written in the past tense and can be in the passive voice. Some examples of the different methods that you can use to gather data are given below. The data collected provides evidence to build your arguments. Collect data, integrate the findings and perspectives from different studies and add your own analysis of its feasibility.

• Explore the literature/news/internet sources to know the topic in depth
• Give a description of how you selected the literature for your project
• Compare the studies, and highlight the findings, gaps or limitations.
• An in-depth, detailed examination of specific cases within a real-world context.
• Enables you to examine the data within a specific context.
• Examine a well defined case to identify the essential factors, process and relationship.
• Write the case description, the context and the process involved.
• Make sense of the evidence in the case(s) to answer the research question
• Gather data from a predefined group of respondents by asking relevant questions
• Can be conducted in person or online
• Why you chose this method (questionnaires, focus group, experimental procedure, etc)
• How you carried out the survey. Include techniques and any equipment you used
• If there were participants in your research, who were they? How did you select them and how may were there?
• How the survey questions address the different aspects of the research question
• Analyse the technology / policy approaches by visiting the required sites
• Make a detailed report on its features and your understanding of it

Results and Analysis

• Present the results of the study. You may consider visualising the results in tables and graphs, graphics etc.
• Analyse the results to obtain answer to the research question.
• Provide an analysis of the technical and financial feasibility, social acceptability etc

Discussion, Limitation(s) and Implication(s)

• Discuss your interpretations of the analysis and the significance of your findings
• Explain any new understanding or insights that emerged as a result of your research
• Consider the different perspectives (social, economic and environmental)in the discussion
• Explain the limitation(s)
• Explain how could what you found be used to make a difference for sustainability

Conclusion and Recommendations

• Summarise the significance and outcome of the study highlighting the key points.
• Come up with alternatives and propose specific actions based on the alternatives
• Describe the result or improvement it would achieve
• Explain how it will be implemented

Recommendations should have an innovative approach and should be feasible. It should make a significant difference in solving the issue under discussion.

• List the sources you have referred to in your writing
• Use the recommended citation style consistently in your report

Appendix (if necessary/any)

Include any material relating to the report and research that does not fit in the body of the report, in the appendix. For example, you may include survey questionnaire and results in the appendix.

• << Previous: Structure of a report
• Next: Structure of report (Site visit) >>
• Last Updated: Jan 12, 2024 11:52 AM
• URL: https://libguides.ntu.edu.sg/report-writing

You are expected to comply with University policies and guidelines namely, Appropriate Use of Information Resources Policy , IT Usage Policy and Social Media Policy . Users will be personally liable for any infringement of Copyright and Licensing laws. Unless otherwise stated, all guide content is licensed by CC BY-NC 4.0 .

Literature review as a key step in research processes: case study of MA dissertations written on EFL of Saudi context

Saudi Journal of Language Studies

ISSN : 2634-243X

Article publication date: 1 June 2022

Issue publication date: 4 August 2022

The aim of this study is to find out the most common types of literature review and the accuracy of citing information related to topic in question among Saudi English as a Foreign Language (EFL) postgraduate students at Al-Baha University. This study also aims at revealing the quality of the literature review written by researchers.

Design/methodology/approach

This qualitative study used content analysis to investigate 15 unpublished Master of Arts (MA) dissertations written on EFL of Saudi context. They were analyzed qualitatively using criteria modified from Snyder's (2019) model which is considered a potential method for making theoretical and practical contributions of literature review.

The findings of the study showed that students favored the systematic review over the integrative. Additionally, data showed that students were lacking in paraphrasing and organizing cited information coherently and appropriately. Moreover, students' performance was better in design, conduct, and data abstraction and analysis criterion, whereas they seemed rather weak in structuring and writing the review criteria.

Originality/value

The significance of the study is to provide researchers with methodological guidance and reference to write a comprehensive and appropriate literature review. Based on the findings, this study concluded with some implications that aim to assist researchers in carrying out their studies professionally. Furthermore, the findings provide decision-makers in higher education institutions with important practical implications. In light of the study's findings, it is suggested to carry out further research investigating postgraduate students to find out their perceptions and attitudes regarding the quality standards of scientific research writing and the paraphrasing strategies.

• MA students
• Literature review

Integrative review

Semi-systematic review.

• Systematic review
• Literature review quality
• Paraphrasing

Alsalami, A.I. (2022), "Literature review as a key step in research processes: case study of MA dissertations written on EFL of Saudi context", Saudi Journal of Language Studies , Vol. 2 No. 3, pp. 153-169. https://doi.org/10.1108/SJLS-04-2022-0044

Emerald Publishing Limited

Copyright © 2022, Ahmed Ibrahim Alsalami

Published in Saudi Journal of Language Studies . Published by Emerald Publishing Limited. This article is published under the Creative Commons Attribution (CC BY 4.0) licence. Anyone may reproduce, distribute, translate and create derivative works of this article (for both commercial and non-commercial purposes), subject to full attribution to the original publication and authors. The full terms of this licence may be seen at http://creativecommons.org/licences/by/4.0/legalcode

Introduction

The way a researcher is building his/her research and linking it to current knowledge is like building a block of academic research activity, no matter which discipline it relates to, thus it is a priority step ( Snyder, 2019 ). In a definition by Liberati et al. (2009) cited in Snyder (2019) “ A systematic review can be explained as a research method and process for identifying and critically appraising relevant research, as well as for collecting and analyzing data from said research .” (p. 334). A literature review is an important part of any research as it is considered a foundation of the type of research.

As in Snyder (2019) , literature review is a written text of a published study that includes current knowledge and up-to-date information about the latest findings of science on a particular topic, including substantial discoveries as well as theoretical and practical contributions from scholarly research groups. A literature review as defined by Hart (1998) (Cronin et al ., 2008 cited in Ramdhani et al ., 2014 ) “ is an objective and thorough summary and critical analysis of the relevant, available research and non-research literature on the topic being studied ” (p. 48). A literature review requires a compound series of abilities to learn topics to explore and acquire and retrieve literature searching skills. Additionally, it requires the ability to develop, analyze and synthesize data to be keen on reporting and writing normally at a limited scale of time. Scholars divided the literature review into two types. The first is “Traditional or Narrative Literature Review”. This type of review criticizes and summarizes the body of the literature to draw conclusions about the topic under consideration. The basic aim of this review is to support a reviewer with a complete review to understand the knowledge and to show the implication of new inquiries. The second one is “Systematic Literature Review” which reviews the literature in a specific subject area to employ a more rigorous and well-defined approach. A systematic literature review is often used to solve a specific medical practice question ( Parahoo, 2006 ; Davis et al ., 2014 ; Almelhes, 2020 ). Some studies regard “meta-analysis” as a type of systematic review, which is primarily a statistical method that entails evaluating the research results among many studies on the very same topic using standardized statistical tests in drawing conclusions and identify patterns and trends between research results ( Polit and Beck, 2006 ; Dundar and Fleeman, 2017 ; Almelhes, 2020 ).

The most common types of literature review among Saudi EFL postgraduate students in Al-Baha University,

The accuracy of citing information related to the topic in question and

The quality of the literature review written by the MA researchers at Al-Baha University.

What are the most common types of literature review among Saudi EFL students at Al-Baha University?

To what extent is the accuracy of citing information related to the topic in question?

To what extent is the quality of the literature review written by the MA researchers at Al-Baha University?

Steps and phases of doing a literature review

Designing the review.

Why should this literature be reviewed? Do we really need literature in this area of our topic? And what literature review would be the great type for contribution? Indeed, these questions would be better borne in the mind of a researcher before starting to review the literature because they determine the likelihood of the review and the impact it might have on the research community ( Antons and Breidbach, 2018 ). As it is a hard work to conduct a literature review, the topic must interest both author and the reader. Hence, first of all, it is better to scan the points to relate to existing knowledge. Moreover, Palmatier et al . (2018) stated that any criterion related to the on-focus topic should be directed by the research questions.

Conducting the review

Conducting a review is required after deciding on the purpose, questions and type of approach that better suits the topic in question. Additionally, it is better to appropriately test the review process and protocol before performing the main review. To ensure the quality and reliability of the search protocol, it is important to use two reviewers to select articles depending on the nature and scope of the review ( Antons and Breidbach, 2018 ; Almelhes, 2020 ).

Analyzing the literature

To conduct appropriate analysis, it is important to consider how the articles will be used. Meanwhile, abstracting information needs to be professionally measured ( Palmatier et al ., 2018 ). They can be put into descriptive information (e.g. authors, year of publication, topic or type of study), or in effects and findings format, conceptualizations or theoretical perspective. Additionally, it is better to avoid any differences in coding and monitoring the data abstraction carefully during the review process in order to ensure quality and reliability. Researchers should ensure that their literature is appropriate to answer the selected research question.

Writing a review

The final review of any article depends on an approach that requires types of different information and different levels of details like standards and guidelines that explicitly address how literature reviews should be reported and structured (see Table 1 , below). Standards and guidelines for systematic narrative reviews ( Wong et al. , 2013 ) or guidelines for integrative reviews ( Torraco, 2005 ) should be considered in the final review too. Moreover, how literature was identified, analyzed, synthesized and reported by a researcher is necessary to describe transparently the process of designing the review literature. Literature reviews can result in a historical analysis of the development within a research field ( Carlborg et al ., 2014 ; Almelhes, 2020 ) or can be any agendas for further research ( McColl-Kennedy et al. , 2017 ), besides, conceptual model or categorization ( Snyder et al. , 2016 ; Witell et al ., 2016 ), or can be evidence of an effect ( Verlegh and Steenkamp, 1999 ).

The process of undertaking a literature review

Regardless of the method used to carry out the literature review, there seems to be a myriad of activities to be carried out and decisions made in order to build an assessment that satisfies the criteria for publication (for specific considerations with regards to each phase, as seen in Table 2 ). There are four phases that demonstrate and discuss the essential decisions and questions associated with conducting a literature review (as in Table 2 below): (1) designing the review, (2) conducting the review, (3) analysis and (4) structuring and writing the review ( Snyder, 2019 ). This procedure arose from real-world and practical experience and is a synthesis of and impact by diverse rules and specifications for literature reviews (e.g. Liberati et al. , 2009 ; Tranfield et al. , 2003 ; Wong et al. , 2013 ).

Types of literature review

Systematic literature review.

As described by Davis et al. , (2014) and later by Dundar and Fleeman (2017) , systematic reviews have first developed within medical sciences to synthesize research findings in a systematic, transparent and reproducible way. It can be a process for identifying and critically appraising relevant research for collecting and analyzing data from previous studies ( Liberati et al. , 2009 ; Almelhes, 2020 ). It aimed at identifying all empirical evidence that fits the pre-specified inclusion criteria to answer a particular research question or hypothesis. Bias can be minimized to provide reliable findings from conclusions and decisions ( Liberati et al. , 2009 ). Often statistical approaches are used to integrate the results of the topics in question. It combines results from different studies to evaluate and compare and identify patterns, disagreements or relationships ( Davis et al. , 2014 ) to assess them. It can be used to determine the continuity of effects across studies and to discover types of future studies that are required to be conducted to demonstrate the effect. Besides, techniques were used to discover which study-level or sample characteristics affect the phenomenon ( Davis et al. , 2014 ). The primary goal of a systematic review is to provide as comprehensive a list as possible of all studies whether published or unpublished, and these studies concerning a specific subject ( Ryan et al ., 2007 ; Dundar and Fleeman, 2017 ).

A systematic review needs to use standards as a roadmap for collecting studies ( Livinski et al ., 2015 ). Systematic review design has covered the following criteria: (1) studies related to students' attitudes; (2) the engagement of the learning process and (3) the outcomes of studies regarding speaking, writing and reading skills ( Antons and Breidbach, 2018 ; Almelhes, 2020 ).

The semi-systematic or narrative review approach hinders a full systematic review process. It is designed for different conceptualized and various studies that were studied by groups of researchers within various disciplines ( Wong et al. , 2013 ; Dundar and Fleeman, 2017 ).

Since it is hard to review every single article relevant to the topic, a different strategy must be developed ( McColl-Kennedy et al. , 2017 ). It aims at overviewing a topic and how research has progressed over time and developed. Generally, it seeks to identify and understand all potentially relevant research traditions and synthesize them by measuring effect size ( Wong et al. , 2013 ) and provides a considerate understanding of complex areas. It is potentially contributed to a useful analysis for detecting themes, and theoretical viewpoints of specific research disciplines as well as to identifying components of a theoretical concept ( Ward et al ., 2009 ). Thus, gain the ability to map a field of research, synthesize the state of knowledge and create an agenda for further research or the ability to provide a historical overview of a specific topic.

An integrative review is closely related to the semi-structured (integrative or critical review) approach. Usually, it has a different purpose from the semi-structured review which aims to assess, critique, and synthesize the literature in a way to develop new theoretical frameworks and perspectives ( Torraco, 2005 ). Generally, integrative literature reviews are intended to address mature or new topics. Additionally, seek to emerge topics to overview the knowledge base, critically review and potentially reconceptualize and expand on the theoretical foundation of the specific topic. It requires a more creative collection of data ( Whittemore and Knafl, 2005 ). A review of good literature does not summarize the sources, but rather analyzes, collects and evaluates them accurately to form a clear and general picture of existing knowledge or science on this topic.

Text borrowing skills

Text borrowing and incorporating other people's written ideas into one's own scholarly work are useful qualities to have in the world of academia, particularly for those pursuing higher education. Text borrowing expertise widely used in academic writing includes direct quoting, paraphrasing and summarizing. When contrasted to paraphrasing, directly quoting from the primary material is far more feasible, easier and less complex. There is really nothing inappropriate with integrating quotations; nevertheless, as Davis and Beaumont (2007) point out, overusing quotations does not really represent highly proficient writing. Rather, academic writing motivates the use of paraphrasing, drawing conclusions or synthesizing skill sets.

Paraphrasing is described as reiterating a statement in such a manner that both sentences are lexically and syntactically distinct whilst also remaining semantically equivalent ( Amoroso, 2007 ; Davis and Beaumont, 2007 ; McCarthy et al ., 2009 ). At least two echoes are implied by this description: reading process skills and writing ability. As a result, according to McCarthy et al . (2009) , paraphrasing is often used to aid comprehension, enhance previous knowledge and assist the development of writing skills.

According to cognitive psychology literature, paraphrasing is mentally demanding. As the content to be paraphrased has become more complicated, students are more likely to use simplified processing, resulting in patchwork written text (Marsh, Landau and Hick in Walker, 2008 ). Walker adds that just imagining about paraphrasing takes a substantial amount of cognitive vitality, and when the physical writing process starts, individuals have restricted opportunity to undertake thoughtful, systematic processing to ascertain if they paraphrased correctly. These complicated characteristics of paraphrasing cause some challenges. In the Japanese context, Iwasaki (1999) discovered four major areas of difficulty: varying behavioral patterns of parts of speech, subject limitation, context-specific paraphrasing and “blank” locating. There seems to be little proof, and data obtained from extensive research dedicated to examining paraphrasing-related concerns in the Indonesian context. Despite an abundance of survey participants, Kusumasondjaja's (2010) survey did not test students' paraphrasing abilities. It appears that paraphrasing is not represented, is described vaguely or is purely regarded as changing the existing source without stating the extent of adjustment.

In the Saudi context, Alaofi (2020) investigated the key problems that Saudi graduate students usually face when summarizing and paraphrasing source texts in EFL. Nine Saudi students attending university degrees in multiple fields were questioned using a qualitative approach. The study's findings revealed that a variety of barriers may exacerbate students' challenges with the skills under examination. These were students' insufficient English proficiency is the first root of complexities in summarizing and paraphrasing original text, followed by issues with students' writing styles and, finally, poor reading comprehension skillsets.

Methodology

As mentioned above, the purpose of this study is to analyze and synthesize findings from the content that is written in the literature review section of 15 unpublished MA studies. These studies were written in the Saudi context and conducted by MA postgraduate students of Al-Baha University. Additionally, to find out the most common types of literature review used by Saudi EFL postgraduate students in Al-Baha University, and to measure the accuracy of citing information related to topics in question, besides finding out the criteria and assess the quality of literature review written by MA researchers, to come out with rich findings that can guide undergraduate students in writing and reviewing knowledge related to their theses and research papers. Additionally, it can help postgraduates and other academic researchers to build a tidy content of literature and coherent procedures for research writing. Thus, this research is done qualitatively using content analysis taking into account the discipline, type of literature review, and contribution to see how successfully these researchers attract readers' attention and satisfy their needs, and in the long run, increase the quality of research and to develop better and more accurate hypotheses and questions.

To measure the research questions, 15 MA dissertations were selected randomly and carefully analyzed accordingly. The analysis of these 15 studies focused mainly on finding out the common types of literature review used by Saudi EFL students in Al-Baha University, and finding the accuracy of citing information, besides assessing the quality of the literature review of the selected MA research. Synder's (2019) model for assessing the quality of literature review is used as a criterion to analyze these MA studies. All are written in the field of English Language Teaching (ELT) settings. Therefore, it will be a potential step in making theoretical and practical contributions to literature review as a method to clarify what a literature review is, how it can be used and what criteria should be used to evaluate its quality. Thus, in this paper, the contribution differentiates between several types of literature review methodologies such as systematic, semi-systematic, and traditional/integrative approaches and how the procedures and the quality were shown (see Appendix ). Besides, presenting real practices that may be met when reviewing literature in EFL research. Additionally, it provides context and guidance to students and academics to use the literature review as a method to synthesize their research in question.

As in Appendix , the criteria used contained four phases: (1) design (includes 6 dimensions); (2) conduct (includes 5 dimensions); (3) data abstraction and analysis (includes 5 dimensions); and (4) structuring and writing the review (includes 5 dimensions). To show that the criterion has been met, the researcher used the symbol (√) as an indication system or vice versa (×) if it was not. The 15 kinds of research were coded using numbers (i.e. each research was given a number from 1 to 15). Then each research was checked according to the dimension of each criterion of each quality. These 15 unpublished MA studies were collected from the College of Arts and Humanities in Al Aqiq main campus, where the postgraduate dissertations were archived, and these studies were conducted during the period from 2013 to 2018. The reason for not selecting newer studies after 2018 is that this paid master's program has been discontinued and has resumed in mid-2021. To ensure the quality of the assessment and the analysis according to Synder's standard, the researcher got help from jury members of three PhD holders (voluntarily) who work in the Department of English at the College of Science and Arts in Qilwah. They had more than ten years of experience in the field of teaching and scientific research. The research took place in a round-held table for a number of meetings and asked them to review and evaluate the MA research according to Synder's criteria. The evaluation continued for three months, and each phase and its dimensions were discussed in separate sessions. The evaluation and discussion took place during the first term of the academic year 2021. Step by step the researcher continuously discussed with the jury members their evaluation (see Appendix ).

The analysis section was divided into two parts. The first part displayed the data gathered to measure the first and the second questions, whereas the second part displayed the third question.

Discovering common types of literature review and evaluating the accuracy of citing information

Part 1 : The main types of literature review (traditional or narrative, systematic, meta-analysis and meta-synthesis) were scrutinized and analyzed in light of their qualities and procedures. In this paper, three types are chosen to be judged accordingly. They are systematic, semi-systematic and traditional/integrative approaches. As mentioned above, the 15 MA projects were handed over to the reviewers (the researcher's colleagues). After long and regular sessions, they concluded their results to the researcher. They revealed that studies 1, 10 and 15 showed a masterpiece reflection of the systematic review approach. In this sense, these studies synthesized and compared evidence between the two studies. Another example is that these studies in the introduction section produced a clear and rationale connection between the topic and literature written in the same field of the study. These studies also showed that the information provided is reliable and based on proven facts. Additionally, the information is verified against other reliable sources. To be more realistic, we must evaluate all sources before deciding whether to incorporate what was found into the literature review ( Synder, 2019 ). Moreover, resources need to be evaluated to make sure that they contain information, which is valuable and pertinent, in this point, this study is consistent with what was found by other researchers ( Liberati et al. , 2009 ; Tranfield et al. , 2003 ; Wong et al. , 2013 ; Synder, 2019 ). These studies presented a rich literature that is displayed in various types of periodicals that include scholarly journals of high impact factors and intensive readability.

Generally, studies (1, 3, 4, 6, 8, 10, 11, 12, 13, 14 and 15) used systematic reviews to answer their highly structured and specific research questions. They undertook a more rigorous approach in reviewing the literature they presented in their research. In contrast, a traditional or narrative literature review usually adopts a critical approach in a way that analyzes and summarizes to address intensive information to shed light on new ideas, bridge gaps or/and cover weaknesses of previous research, studies endeavored a very high and accurate criterion of evaluating literature review Ryan et al. (2007) . On the other hand, studies (2, 5, 7 and 9) used both semi-systematic and integrative/traditional literature reviews. This clearly showed that the research questions were broad. On the other hand, in the introduction section, these studies used a semi-systematic literature review. For accuracy purposes, these studies presented a piece of reliable information. All the information displayed in these studies was error-free. Additionally, it is easy to say that the information shown was based on proven facts and can be verified against other reliable sources. All that cited in these studies in the literature review section was taken from famous and well-known periodicals. They can be completely described as facts shown without any bias. When looking back to what the researchers presented, it is easy to see that information presented was currently published to show the currency matter of the researchers' topics. The coverage of information has met in-depth the information needed to build up a literature review process. Accordingly, the researchers reviewed rich and accurate literature written about the focus topics to rationalize their objectives in conducting their research. All the information shown by researchers was presented without any bias. Thus, each study presented more than four references to show the accurateness of the literature. Additionally, the information presented is highly met and covered the needed information, and provided a basic and in-depth coverage. To meet the aims of systematic review (as in Dundar and Fleeman, 2017 ), to some extent, these studies provided a complete list of all possible published and unpublished studies relating to the researcher's subject matter.

To deal with the accuracy of citing information, in studies (2, 3, 4, 5, 9, 10, 11, 12, 14 and 15) one can find that, from the beginning, in the introduction section, these studies started citing from very recently published researches. Most interestingly, the researchers used the paraphrasing method to cite information related to the researchers' topic. However, they did not paraphrase appropriately. These studies used a paraphrasing method to make the information cited more reliable, error-free, based on proven facts and can be verified against other reliable sources. In this sense, these studies presented information that can be more accurate. But unexpectedly, those who used the paraphrasing method lacked professionality in treating the original text and formulating it using their own words (i.e. there is an apparent weakness in meaning between the original source and the paraphrased text). Again, the studies showed that researchers intended the purpose of the information in a precise way initiating that in the introduction. The studies also presented facts that were proven by famous writers.

Assessing the quality of a literature review

Part 2: As empirical research, literature reviews need assessment and evaluation ( Palmatier et al. , 2018 ). The literature review quality must have both depth and rigor to determine a suitable strategy for choosing topics and apprehending data and insights and to recite previous studies slightly. The quality of the literature review needs to be replicable to make the reader easily replicate the topic and reaches similar findings. Additionally, they must be useful for scholars and practitioners. Normally, the evaluation of different types of literature reviews is considered to be challenging. However, some guidelines could be used as a starting point to help researchers in evaluating literature reviews, to examine and to assess the review criteria for rigor and depth. To assess the literature review quality related to MA studies (the 15 selected samples) in question, Snyder (2019 , p. 338) suggested some guidelines as seen in Appendix .

Therefore, to find out a suitable step-by-step approach that can guide students and academics in undertaking a valid, comprehensive and helpful literature review, appropriate literature reviews have been gathered for this inquiry to investigate the criteria and quality of literature presented by selected MA studies (see Appendix ). Depending on the purpose of the topic, various literature studies may be highly useful to suggest which strategy may suit the analysis and synthesis stages that greatly help in the selection and writing of the literature review on EFL context, mainly Saudi context. Thus, the selected reviews were scrutinized and analyzed considering their qualities and procedures. In this paper, only 15 MA studies were chosen to be measured accordingly.

As in Appendix , the quality of these projects was checked and graded by the reviewers (the researchers' colleagues). Looking at the reviewers' evaluation of these dissertations, one can easily find that only one out of the 15 showed complete performance and was valuable in all criteria. Meanwhile, the others showed strength in the first and second dimensions of the design criteria. However, their performance in the other parameters deteriorated greatly. In total, seven out of them performed moderately in design criteria (i.e. they achieved in dimensions, 1, 2 and 6, whereas they failed in the other 3, 4 and 5); as the other seven researchers performed in four dimensions moderately. Concerning the conduct criteria, they did very well. Therefore, ten out of the fifteen researchers fulfilled perfectly in all dimensions, however, only five performed somehow moderately in only four out of the five dimensions in the conduct criteria. Additionally, seven out of the fifteen achieved in all dimensions in data abstraction and analysis, whereas three contented in only four dimensions, meanwhile other three of them fulfilled only three, while the other two achieved two dimensions. Although researchers did very well in design, conduct, and data abstraction and analysis criterion, they seemed very weak in structuring and writing the review. They only achieved in the fourth and fifth dimensions of this criteria. However, they got zero achievements in the first dimension. Additionally, only six out of the fifteen researchers fulfilled the third dimension, whereas only five achieved the second one.

Findings and discussion

As mentioned above, the purpose of this study is to find out the common types of literature review used by Saudi EFL postgraduate students in Al-Baha University; and to find out the accuracy of citing information related to the topics in question; as well as to assess the quality of the literature review written by selected researchers. From the analysis, it was found that most researchers (11 out of 15) used a systematic review of the literature. Systematic reviews are the thorough and openly transparent type of literature review. Moreover, the most reliable and comprehensive statement about what works is that systematic reviews embark on identification, synthesis and assessment of the available proof, or qualitative and/or quantitative, as a way of generating a well-researched, and empirically derived answer to a specified research question (Petrosino et al. , cited in van der Knaap, 2008 ). The analysis also showed that most researchers utilized paraphrasing in their citing information. Even though it eases work for the researcher, paraphrasing may poorly present information if not used well. As advised, it is better to understand the readings and put them in your own words to preserve the accuracy of the information. Thus, understanding information and then properly paraphrasing will make the work look more original and refined. In this study, the researchers in many parts of the research failed to do an accurate performance in paraphrasing (i.e. there is an apparent weakness in meaning between the original source and the paraphrased text). This demonstrated that there was no accuracy in the paraphrasing used to cite information on the topics in question.

Regarding the quality of the literature review written by selected researchers, the data were gathered using a checklist by the evaluators who voluntarily distributed it into the inquiry to help the researcher to rate the performance of the 15 MA students in their dissertations. Generally, the results showed that students (the MA researchers) were keen on the conduct phase and then to some extent on data abstraction and analysis. Therefore, they know how to conduct their research, especially they have proper measures to ensure quality data abstraction. Moreover, chose data analysis techniques appropriately concerning the overall research questions and the data abstracted. Thus, they accurately search the process for types of reviews, and they did the inclusion and exclusion processes of articles transparent which makes their sample appropriate and in concordance with the overall purpose of the review. Additionally, in the design, concerning the relationship to the overall research field, their literature review was needed, and it makes a substantial, practical and theoretical contribution; the motivation, the purpose and the research questions were clearly stated and motivated; the methodology and the search strategy were clearly and transparently described. On the other hand, they were weak in phase 1 (design), item 3 “Does the review account for the previous literature review and other relevant literature ?”, and they did not clearly state the approaches for the literature review. Finally, the study found that they showed a weak achievement in structuring and writing the review, especially they did not organize articles coherently about the overall approach and research question, and the overall method of conducting the literature review was not sufficiently described, thus their studies could not be replicated.

Therefore, as shown in the purpose of this research, the review of intellectual production is most often the introduction to various theses or peer-review research articles, before presenting the methods and results, and its use is common in most academic research. Thus, the literature review represents one of the important parts of the scientific research plan ( Baumeister and Leary, 1997 ; Torraco, 2005 ). It is the second part that is related to the theoretical framework of the presented research methodology. Meanwhile, it is directly and closely related to the topic. Additionally, it represents an information-rich ground for those who have the desire to know all aspects of the problem or hypothesis in question. It consumes time and requires strong analytical skills from the researchers to make a great contribution successfully as mentioned by other scholars ( Boyd and Solarino, 2016 ; Mazumdar et al. , 2005 , pp. 84–102; Rodell et al ., 2016 ). As in the study questions, and to rationalize the topic, the findings concluded in this paper showed that the analysis and criticism of the literature review may require personal experiences, and others depend on the methodological foundations. The analysis and the criticism should include various dimensions (content, methodology, the sample, reliability and results). This was evident in the performance of these students in analyzing, criticizing and citing the previous studies they refer to. Thus, a researcher should have appropriate insight and wisdom to comment on previous studies and critique them constructively through compelling scientific evidence as well as to be objective and distant from any internal ideologies or personal bias. Therefore, some ideas and techniques that contribute to the process of editing, analyzing and criticizing literature review must be known by researchers ( MacInnis, 2011 ). Additionally, more attention should be given to structuring and writing the review mainly the organization of the review in relation to the overall approach and research questions.

Implications

The study came up with some implications that can help researchers in conducting their studies skillfully. These implications were drawn from the study's findings which may be very important for practice or conducting a literature review.

First: How to criticize the literature?

When looking at the literature review, one should focus on five main points that a study can follow. They are (1) content, (2) methodology, (3) the study sample, (4) credibility and (5) results. Content criticism: in this case, the researcher must express his/her point of view that the content of the previous studies does not include the technical framework that must be followed, and in that case, the study loses the advantage of comprehensiveness and moves away from objectivity in the way it is refuted.

Criticism related to methodology

Here, the researcher must clarify the negative and positive points in the scientific method followed in previous studies, and it is not a requirement that the literature might be negative or positive in its entirety. Accordingly, this is subject to the researcher's opinion, which is an expression of his/her point of view, and he/she has to present this according to convincing evidence which varies from one researcher to another.

Criticism related to the study sample

The researcher must mention any deficiencies in the sample under study which may be ineffective in judging previous literature, and it was possible to increase the sample size. To clarify a matter related to the research problem, the sample may not be represented in an appropriate statistical way, etc.

Credibility criticism

The researcher must verify the reliability of previous studies, and the method of ascertaining. This differs according to the methodology followed by the review studies (i.e. there is the descriptive, experimental and historical approach. For example, the historical method is distinguished by its credibility from others, and the researcher must refute that matter and follow the precise criteria in judging that, etc.). To judge the reliability of literature, the researcher must be familiar with all scientific research methods, their advantages and disadvantages, and the research hypotheses and theories that are compatible with those approaches.

Results criticism

The researcher may disagree with the results shown in previous studies. Because there is an error in the method of analyzing and presenting the data, so, the researcher must clarify the comparison between his/her findings and what was presented in other studies and indicate the extent of objectivity in each of them ( Snyder et al ., 2016 ; Verlegh and Steenkamp, 1999 ; Witell et al. , 2016 ). Additionally, the researcher should address only the previous studies related to the research topic, and the link must be clear to the reader, so it makes no sense to refer to previous research or studies that do not touch the research problem from near or far.

Second: How to comment on literature?

Previous studies help clarify the theoretical foundations of the subject of the research to be carried out by the researcher.

They save time and effort for the researcher by choosing the framework for the topic of the research plan.

They are a wake-up call for the researcher when writing a paper by defining a method that would avoid the researcher making mistakes made by previous researchers.

Present the correct methodological approach to the topic of research in general.

They give the researcher an exemplary method to extract recommendations, findings and other proposals related to the research.

Literature helps the researcher in identifying references for his/her research and facilitates the process of writing.

They have an important role in the researcher's comparison process between the research he provides and those studies and sources.

As many EFL MA researchers find it difficult to choose and handle a suitable literature review that approves their writing quality, thus, this study was conducted to find out a suitable step-by-step approach that can help to undertake a valid, comprehensive and helpful literature review. In conclusion, EFL MA researchers need to search for the quality and trustworthiness of their reviews to build a rich and adequate literature review. As found in this paper, it is seen that most MA Saudi researchers favored using the systematic review rather than the integrative type. More or less, they try to avoid comparing the review rather than identifying and synthesizing, as it may seem a more complicated process. Obviously, reviewing any article that could be relevant to the topic is not a simple task; therefore, a different strategy must be developed and used carefully to fulfill the quality of literature review along with the topic in question. More interestingly and generally, the researcher found that a semi-systematic review method often possesses similarities to approaches used in qualitative research ( Dundar and Fleeman, 2017 ), but it can also be combined with a statistical meta-analysis approach. Due to the integrative approach liability to yield a creative collection of data, it is widely used to combine perspectives and insights from previous research. Thus, the integrative approach seems to be the best method that can be used in the field of EFL because its purpose is to compare and combine rather than cover all related topics. Additionally, as the study found that students did not accurately paraphrase/summarize appropriately from other sources, additional sessions impeding paraphrasing procedures and processes will have valuable benefits and will make students better at writing research in the future. Concerning the phases of the quality of conducting research, it is important to ensure the proper measurement that qualifies the quality of data abstraction and analysis techniques that deal with the overall research questions accurately. Furthermore, searching for proper types of reviews, article transparency and the appropriate sample should fit the purpose of the review. Finally, among the broader implications of the study, it is expected that the construction of master's programs (courses path) should be reviewed, and focus should be given to teach students the quality standards of research writing and how to analyze and critique them in a better way.

Approaches to literature reviews

Note(s): *Adopted from Snyder's (2019 , p. 338) model “Guidelines to assess the quality of a literature review”

Alaofi , A.O. ( 2020 ), “ Difficulties of summarizing and paraphrasing in English as a Foreign Language (EFL): Saudi graduate Students' perspectives ”, International Journal of English Language Education , Vol.  8 No.  2 , pp.  193 - 211 , doi: 10.5296/ijele.v8i217788 .

Almelhes , S. ( 2020 ), “ Second language acquisition through the flipped learning paradigm: a systematic literature review ”, Journal of the Islamic University for Social and Educational Sciences , 2nd ed. , Almadinah Almonorah , pp.  537 - 569 , available at: http://search.mandumah.com/Record/1091211 .

Amoroso , J. ( 2007 ), “ Paraphrasing practice. The College of Saint Rose writing Center ”, available at: http://www.strose.edu/officesandresources/acade mic_support_center/writingsupport .

Antons , D. and Breidbach , C.F. ( 2018 ), “ Big data, big insights? Advancing service innovation and design with machine learning ”, Journal of Service Research , Vol.  21 , pp.  17 - 39 , doi: 10.1177/1094670517738373 .

Baumeister , R.F. and Leary , M.R. ( 1997 ), “ Writing narrative literature reviews ”, Review of General Psychology , Vol.  1 , pp.  311 - 320 , doi: 10.1037/1089-2680.1.3.311 .

Boyd , B.K. and Solarino , A.M. ( 2016 ), “ Ownership of corporations: a review, synthesis, and research agenda ”, Journal of Management , Vol.  42 , pp.  1282 - 1314 , doi: 10.1177/0149206316633746 .

Carlborg , P. , Kindström , D. and Kowalkowski , C. ( 2014 ), “ The evolution of service innovation research: a critical review and synthesis ”, The Service Industries Journal , Vol.  34 No.  5 , pp.  373 - 398 , doi: 10.1080/02642069.2013.780044 .

Davies , W.M. and Beaumont , T. ( 2007 ), “ Paraphrasing. Teaching and Learning Unit, Faculty of Economics and Commerce ”, The University of Melbourne , available at: http://tlu.ecom.unimelb.edu.au/ .

Davis , J. , Mengersen , K. , Bennett , S. and Mazerolle , L. ( 2014 ), “ Viewing systematic reviews and meta-analysis in social research through different lenses ”, SpringerPlus , Vol.  3 , p. 511 , doi: 10.1186/2193-1801-3-511 .

Dundar , Y. and Fleeman , N. ( 2017 ), “ Developing my search strategy and applying inclusion criteria ”, in Boland , A. , Cherry , M.G. and Dickson , R. (Eds), Doing a Systematic Review: A Student's Guide , 2nd ed. , SAGE , London , pp.  37 - 59 .

Hart , C. ( 1998 ), Doing a Literature Review , Sage Publications , London .

Iwasaki , H. ( 1999 ), “ Reproduction and paraphrasing. The web of English curriculum development ”, University of Tsukuba, Foreign Language Center , Tsukuba , pp.  1 - 10 , available at: http://www.tulips.tsukuba.ac.jp/limedio/dlam/B15/B1511855/1.pdf .

Kaminstein , D. ( 2017 ), “ Writing a literature review for an applied Master's degree ”, Organizational Dynamics Working Papers 23 , available at: https://repository.upenn.edu/od_working_papers/23 .

Kusumasondjaja , S. ( 2010 ), “ Exploring plagiarism behavior among Indonesian university students: issues and lessons learned ”, paper presented at Indonesian Student International Conference 2010 , available at: http://www.kipi-2010.org/ .

Liberati , A. , Altman , D.G. , Tetzlaff , J. , Mulrow , C. , Gøtzsche , P.C. , Ioannidis , J.P.A. and Moher , D. ( 2009 ), “ The PRISMA statement for reporting systematic reviews and metanalyses of studies that evaluate health care interventions: explanation and elaboration ”, Annals of Internal Medicine , Vol.  151 , W–65 , doi: 10.7326/0003-4819-151-4-200908180-00136 .

Livinski , A. , Ma , J.D. and Terry , N. ( 2015 ), “ Undertaking a systematic review: what you need to know. Office of research services ”, National Institute of Health. U.S Department of Health and Human Services. NIH Library , available at: http://nihlibrary.nih.gov .

MacInnis , D.J. ( 2011 ), “ A framework for conceptual contributions in marketing ”, Journal of Marketing , Vol.  75 , pp.  136 - 154 , doi: 10.1509/jmkg.75.4.136 .

Mazumdar , T. , Raj , S.P. and Sinha , I. ( 2005 ), “ Reference price research: review and propositions ”, Journal of Marketing , Vol.  69 No.  4 , pp.  84 - 102 , doi: 10.1509/jmkg.2005.69.4.84 .

McCarthy , P.M. , Guess , R.H. and McNamara , D.S. ( 2009 ), “ The components of paraphrase evaluations ”, Behavior Research Methods , Vol.  41 No.  3 , pp.  682 - 690 .

McColl-Kennedy , J.R. , Snyder , H. , Elg , M. , Witell , L. , Helkkula , A. , Hogan , S.J. and Anderson , L. ( 2017 ), “ The changing role of the health care customer: review, synthesis and research agenda ”, Journal of Service Management , Vol.  28 No.  1 , pp. 2 - 33 , doi: 10.1108/JOSM-01-2016-0018 .

Palmatier , R.W. , Houston , M.B. and Hulland , J. ( 2018 ), “ Review articles: purpose, process, and structure ”, Journal of the Academy of Marketing Science , Vol.  46 , pp.  1 - 5 , doi: 10.1007/s11747-017-0563-4 .

Parahoo , K. ( 2006 ), Nursing Research – Principles, Process, and Issues , 2nd ed. , Houndsmill , Palgrave .

Polit , D. and Beck , C. ( 2006 ), Essentials of Nursing Research: Methods, Appraisal and Utilization , 6th ed. , Lippincott Williams and Wilkins , Philadelphia .

Ramdhani , A. , Ramdhani , M.A. and Amin , A.S. ( 2014 ), “ Writing a literature review research paper: a step-by-step approach ”, International Journal of Basic and Applied Science , Vol.  03 No.  1 , p. 48 .

Randolph , J.J. ( 2009 ), “ A guide to writing the dissertation literature review ”, Practical Assessment, Research and Evaluation , Vol.  14 No.  13 .

Rodell , J.B. , Breitsohl , H. , Schröder , M. and Keating , D.J. ( 2016 ), “ Employee volunteering: a review and framework for future research ”, Journal of Management , Vol.  42 , pp.  55 - 84 , doi: 10.1177/0149206315614374 .

Ryan , F. , Coughlan , M. and Cronin , P. ( 2007 ), “ Step-by-step guide to critiquing research. Part 2: qualitative research ”, British Journal of Nursing (Mark Allen Publishing) , Vol.  16 No.  12 , pp.  738 - 744 , doi: 10.12968/bjon.2007.16.12.23726 .

Snyder , H. ( 2019 ), “ Literature review as a research methodology: an overview and guidelines ”, Journal of Business Research , Vol.  104 , pp.  333 - 339 , doi: 10.1016/j.jbusres.2019.07.039 .

Snyder , H. , Witell , L. , Gustafsson , A. , Fombelle , P. and Kristensson , P. ( 2016 ), “ Identifying categories of service innovation: a review and synthesis of the literature ”, Journal of Business Research , Vol.  69 , pp.  2401 - 2408 , doi: 10.1016/j.jbusres.2016.01.009 .

Torraco , R.J. ( 2005 ), “ Writing integrative literature reviews: guidelines and examples ”, Human Resource Development Review , Vol.  4 , pp.  356 - 367 , doi: 10.1177/1534484305278283 .

Tranfield , D. , Denyer , D. and Smart , P. ( 2003 ), “ Towards a methodology for developing evidence informed management knowledge by means of systematic review ”, British Journal of Management , Vol.  14 , pp.  207 - 222 , doi: 10.1111/1467-8551.00375 .

van der Knaap , L.M. ( 2008 ), “ Combining Campbell standard and the realist evaluation approach: the best of two worlds? ”, American Journal of Evaluation , Vol.  29 No.  1 , pp.  48 - 57 .

Verlegh , P.W.J. and Steenkamp , J.-B.E.M. ( 1999 ), “ A review and meta-analysis of country-of-origin research ”, Journal of Economic Psychology , Vol.  20 , pp.  521 - 546 , doi: 10.1016/S0167-4870(99)00023-9 .

Walker , A.L. ( 2008 ), “ Preventing unintentional plagiarism: a method for strengthening paraphrasing skills ”, Journal of Instructional Psychology , available at: www.highbeam.com/doc/1G1-193791691.html .

Ward , V. , House , A. and Hamer , S. ( 2009 ), “ Developing a framework for transferring knowledge into action: a thematic analysis of the literature ”, Journal of Health Services Research and Policy , Vol.  14 No.  3 , pp.  156 - 164 , doi: 10.1258/jhsrp.2009.008120 .

Whittemore , R. and Knafl , K. ( 2005 ), “ The integrative review: updated methodology ”, Journal of Advanced Nursing , Vol.  52 No.  5 , pp.  546 - 553 , doi: 10.1111/j.1365-2648.2005.03621.x .

Witell , L. , Snyder , H. , Gustafsson , A. , Fombelle , P. and Kristensson , P. ( 2016 ), “ Defining service innovation: a review and synthesis ”, Journal of Business Research , Vol.  69 , pp.  2863 - 2872 .

Wong , G. , Greenhalgh , T. , Westhorp , G. , Buckingham , J. and Pawson , R. ( 2013 ), “ RAMESES publication standards: meta-narrative reviews ”, BMC Medicine , Vol.  11 , p. 20 , doi: 10.1186/1741-7015-11-20 .

Corresponding author

Related articles, we’re listening — tell us what you think, something didn’t work….

Report bugs here

All feedback is valuable

Please share your general feedback

Join us on our journey

Platform update page.

Visit emeraldpublishing.com/platformupdate to discover the latest news and updates

Questions & More Information

Answers to the most commonly asked questions here

Organizing Your Social Sciences Research Assignments

• Annotated Bibliography
• Analyzing a Scholarly Journal Article
• Group Presentations
• Dealing with Nervousness
• Using Visual Aids
• Grading Someone Else's Paper
• Types of Structured Group Activities
• Group Project Survival Skills
• Leading a Class Discussion
• Multiple Book Review Essay
• Reviewing Collected Works
• Writing a Case Analysis Paper
• Writing a Case Study
• About Informed Consent
• Writing Field Notes
• Writing a Policy Memo
• Writing a Reflective Paper
• Writing a Research Proposal
• Generative AI and Writing
• Acknowledgments

A case study research paper examines a person, place, event, condition, phenomenon, or other type of subject of analysis in order to extrapolate  key themes and results that help predict future trends, illuminate previously hidden issues that can be applied to practice, and/or provide a means for understanding an important research problem with greater clarity. A case study research paper usually examines a single subject of analysis, but case study papers can also be designed as a comparative investigation that shows relationships between two or more subjects. The methods used to study a case can rest within a quantitative, qualitative, or mixed-method investigative paradigm.

Case Studies. Writing@CSU. Colorado State University; Mills, Albert J. , Gabrielle Durepos, and Eiden Wiebe, editors. Encyclopedia of Case Study Research . Thousand Oaks, CA: SAGE Publications, 2010 ; “What is a Case Study?” In Swanborn, Peter G. Case Study Research: What, Why and How? London: SAGE, 2010.

How to Approach Writing a Case Study Research Paper

General information about how to choose a topic to investigate can be found under the " Choosing a Research Problem " tab in the Organizing Your Social Sciences Research Paper writing guide. Review this page because it may help you identify a subject of analysis that can be investigated using a case study design.

However, identifying a case to investigate involves more than choosing the research problem . A case study encompasses a problem contextualized around the application of in-depth analysis, interpretation, and discussion, often resulting in specific recommendations for action or for improving existing conditions. As Seawright and Gerring note, practical considerations such as time and access to information can influence case selection, but these issues should not be the sole factors used in describing the methodological justification for identifying a particular case to study. Given this, selecting a case includes considering the following:

• The case represents an unusual or atypical example of a research problem that requires more in-depth analysis? Cases often represent a topic that rests on the fringes of prior investigations because the case may provide new ways of understanding the research problem. For example, if the research problem is to identify strategies to improve policies that support girl's access to secondary education in predominantly Muslim nations, you could consider using Azerbaijan as a case study rather than selecting a more obvious nation in the Middle East. Doing so may reveal important new insights into recommending how governments in other predominantly Muslim nations can formulate policies that support improved access to education for girls.
• The case provides important insight or illuminate a previously hidden problem? In-depth analysis of a case can be based on the hypothesis that the case study will reveal trends or issues that have not been exposed in prior research or will reveal new and important implications for practice. For example, anecdotal evidence may suggest drug use among homeless veterans is related to their patterns of travel throughout the day. Assuming prior studies have not looked at individual travel choices as a way to study access to illicit drug use, a case study that observes a homeless veteran could reveal how issues of personal mobility choices facilitate regular access to illicit drugs. Note that it is important to conduct a thorough literature review to ensure that your assumption about the need to reveal new insights or previously hidden problems is valid and evidence-based.
• The case challenges and offers a counter-point to prevailing assumptions? Over time, research on any given topic can fall into a trap of developing assumptions based on outdated studies that are still applied to new or changing conditions or the idea that something should simply be accepted as "common sense," even though the issue has not been thoroughly tested in current practice. A case study analysis may offer an opportunity to gather evidence that challenges prevailing assumptions about a research problem and provide a new set of recommendations applied to practice that have not been tested previously. For example, perhaps there has been a long practice among scholars to apply a particular theory in explaining the relationship between two subjects of analysis. Your case could challenge this assumption by applying an innovative theoretical framework [perhaps borrowed from another discipline] to explore whether this approach offers new ways of understanding the research problem. Taking a contrarian stance is one of the most important ways that new knowledge and understanding develops from existing literature.
• The case provides an opportunity to pursue action leading to the resolution of a problem? Another way to think about choosing a case to study is to consider how the results from investigating a particular case may result in findings that reveal ways in which to resolve an existing or emerging problem. For example, studying the case of an unforeseen incident, such as a fatal accident at a railroad crossing, can reveal hidden issues that could be applied to preventative measures that contribute to reducing the chance of accidents in the future. In this example, a case study investigating the accident could lead to a better understanding of where to strategically locate additional signals at other railroad crossings so as to better warn drivers of an approaching train, particularly when visibility is hindered by heavy rain, fog, or at night.
• The case offers a new direction in future research? A case study can be used as a tool for an exploratory investigation that highlights the need for further research about the problem. A case can be used when there are few studies that help predict an outcome or that establish a clear understanding about how best to proceed in addressing a problem. For example, after conducting a thorough literature review [very important!], you discover that little research exists showing the ways in which women contribute to promoting water conservation in rural communities of east central Africa. A case study of how women contribute to saving water in a rural village of Uganda can lay the foundation for understanding the need for more thorough research that documents how women in their roles as cooks and family caregivers think about water as a valuable resource within their community. This example of a case study could also point to the need for scholars to build new theoretical frameworks around the topic [e.g., applying feminist theories of work and family to the issue of water conservation].

Eisenhardt, Kathleen M. “Building Theories from Case Study Research.” Academy of Management Review 14 (October 1989): 532-550; Emmel, Nick. Sampling and Choosing Cases in Qualitative Research: A Realist Approach . Thousand Oaks, CA: SAGE Publications, 2013; Gerring, John. “What Is a Case Study and What Is It Good for?” American Political Science Review 98 (May 2004): 341-354; Mills, Albert J. , Gabrielle Durepos, and Eiden Wiebe, editors. Encyclopedia of Case Study Research . Thousand Oaks, CA: SAGE Publications, 2010; Seawright, Jason and John Gerring. "Case Selection Techniques in Case Study Research." Political Research Quarterly 61 (June 2008): 294-308.

Structure and Writing Style

The purpose of a paper in the social sciences designed around a case study is to thoroughly investigate a subject of analysis in order to reveal a new understanding about the research problem and, in so doing, contributing new knowledge to what is already known from previous studies. In applied social sciences disciplines [e.g., education, social work, public administration, etc.], case studies may also be used to reveal best practices, highlight key programs, or investigate interesting aspects of professional work.

In general, the structure of a case study research paper is not all that different from a standard college-level research paper. However, there are subtle differences you should be aware of. Here are the key elements to organizing and writing a case study research paper.

I.  Introduction

As with any research paper, your introduction should serve as a roadmap for your readers to ascertain the scope and purpose of your study . The introduction to a case study research paper, however, should not only describe the research problem and its significance, but you should also succinctly describe why the case is being used and how it relates to addressing the problem. The two elements should be linked. With this in mind, a good introduction answers these four questions:

• What is being studied? Describe the research problem and describe the subject of analysis [the case] you have chosen to address the problem. Explain how they are linked and what elements of the case will help to expand knowledge and understanding about the problem.
• Why is this topic important to investigate? Describe the significance of the research problem and state why a case study design and the subject of analysis that the paper is designed around is appropriate in addressing the problem.
• What did we know about this topic before I did this study? Provide background that helps lead the reader into the more in-depth literature review to follow. If applicable, summarize prior case study research applied to the research problem and why it fails to adequately address the problem. Describe why your case will be useful. If no prior case studies have been used to address the research problem, explain why you have selected this subject of analysis.
• How will this study advance new knowledge or new ways of understanding? Explain why your case study will be suitable in helping to expand knowledge and understanding about the research problem.

Each of these questions should be addressed in no more than a few paragraphs. Exceptions to this can be when you are addressing a complex research problem or subject of analysis that requires more in-depth background information.

II.  Literature Review

The literature review for a case study research paper is generally structured the same as it is for any college-level research paper. The difference, however, is that the literature review is focused on providing background information and  enabling historical interpretation of the subject of analysis in relation to the research problem the case is intended to address . This includes synthesizing studies that help to:

• Place relevant works in the context of their contribution to understanding the case study being investigated . This would involve summarizing studies that have used a similar subject of analysis to investigate the research problem. If there is literature using the same or a very similar case to study, you need to explain why duplicating past research is important [e.g., conditions have changed; prior studies were conducted long ago, etc.].
• Describe the relationship each work has to the others under consideration that informs the reader why this case is applicable . Your literature review should include a description of any works that support using the case to investigate the research problem and the underlying research questions.
• Identify new ways to interpret prior research using the case study . If applicable, review any research that has examined the research problem using a different research design. Explain how your use of a case study design may reveal new knowledge or a new perspective or that can redirect research in an important new direction.
• Resolve conflicts amongst seemingly contradictory previous studies . This refers to synthesizing any literature that points to unresolved issues of concern about the research problem and describing how the subject of analysis that forms the case study can help resolve these existing contradictions.
• Point the way in fulfilling a need for additional research . Your review should examine any literature that lays a foundation for understanding why your case study design and the subject of analysis around which you have designed your study may reveal a new way of approaching the research problem or offer a perspective that points to the need for additional research.
• Expose any gaps that exist in the literature that the case study could help to fill . Summarize any literature that not only shows how your subject of analysis contributes to understanding the research problem, but how your case contributes to a new way of understanding the problem that prior research has failed to do.
• Locate your own research within the context of existing literature [very important!] . Collectively, your literature review should always place your case study within the larger domain of prior research about the problem. The overarching purpose of reviewing pertinent literature in a case study paper is to demonstrate that you have thoroughly identified and synthesized prior studies in relation to explaining the relevance of the case in addressing the research problem.

III.  Method

In this section, you explain why you selected a particular case [i.e., subject of analysis] and the strategy you used to identify and ultimately decide that your case was appropriate in addressing the research problem. The way you describe the methods used varies depending on the type of subject of analysis that constitutes your case study.

If your subject of analysis is an incident or event . In the social and behavioral sciences, the event or incident that represents the case to be studied is usually bounded by time and place, with a clear beginning and end and with an identifiable location or position relative to its surroundings. The subject of analysis can be a rare or critical event or it can focus on a typical or regular event. The purpose of studying a rare event is to illuminate new ways of thinking about the broader research problem or to test a hypothesis. Critical incident case studies must describe the method by which you identified the event and explain the process by which you determined the validity of this case to inform broader perspectives about the research problem or to reveal new findings. However, the event does not have to be a rare or uniquely significant to support new thinking about the research problem or to challenge an existing hypothesis. For example, Walo, Bull, and Breen conducted a case study to identify and evaluate the direct and indirect economic benefits and costs of a local sports event in the City of Lismore, New South Wales, Australia. The purpose of their study was to provide new insights from measuring the impact of a typical local sports event that prior studies could not measure well because they focused on large "mega-events." Whether the event is rare or not, the methods section should include an explanation of the following characteristics of the event: a) when did it take place; b) what were the underlying circumstances leading to the event; and, c) what were the consequences of the event in relation to the research problem.

If your subject of analysis is a person. Explain why you selected this particular individual to be studied and describe what experiences they have had that provide an opportunity to advance new understandings about the research problem. Mention any background about this person which might help the reader understand the significance of their experiences that make them worthy of study. This includes describing the relationships this person has had with other people, institutions, and/or events that support using them as the subject for a case study research paper. It is particularly important to differentiate the person as the subject of analysis from others and to succinctly explain how the person relates to examining the research problem [e.g., why is one politician in a particular local election used to show an increase in voter turnout from any other candidate running in the election]. Note that these issues apply to a specific group of people used as a case study unit of analysis [e.g., a classroom of students].

If your subject of analysis is a place. In general, a case study that investigates a place suggests a subject of analysis that is unique or special in some way and that this uniqueness can be used to build new understanding or knowledge about the research problem. A case study of a place must not only describe its various attributes relevant to the research problem [e.g., physical, social, historical, cultural, economic, political], but you must state the method by which you determined that this place will illuminate new understandings about the research problem. It is also important to articulate why a particular place as the case for study is being used if similar places also exist [i.e., if you are studying patterns of homeless encampments of veterans in open spaces, explain why you are studying Echo Park in Los Angeles rather than Griffith Park?]. If applicable, describe what type of human activity involving this place makes it a good choice to study [e.g., prior research suggests Echo Park has more homeless veterans].

If your subject of analysis is a phenomenon. A phenomenon refers to a fact, occurrence, or circumstance that can be studied or observed but with the cause or explanation to be in question. In this sense, a phenomenon that forms your subject of analysis can encompass anything that can be observed or presumed to exist but is not fully understood. In the social and behavioral sciences, the case usually focuses on human interaction within a complex physical, social, economic, cultural, or political system. For example, the phenomenon could be the observation that many vehicles used by ISIS fighters are small trucks with English language advertisements on them. The research problem could be that ISIS fighters are difficult to combat because they are highly mobile. The research questions could be how and by what means are these vehicles used by ISIS being supplied to the militants and how might supply lines to these vehicles be cut off? How might knowing the suppliers of these trucks reveal larger networks of collaborators and financial support? A case study of a phenomenon most often encompasses an in-depth analysis of a cause and effect that is grounded in an interactive relationship between people and their environment in some way.

NOTE:   The choice of the case or set of cases to study cannot appear random. Evidence that supports the method by which you identified and chose your subject of analysis should clearly support investigation of the research problem and linked to key findings from your literature review. Be sure to cite any studies that helped you determine that the case you chose was appropriate for examining the problem.

IV.  Discussion

The main elements of your discussion section are generally the same as any research paper, but centered around interpreting and drawing conclusions about the key findings from your analysis of the case study. Note that a general social sciences research paper may contain a separate section to report findings. However, in a paper designed around a case study, it is common to combine a description of the results with the discussion about their implications. The objectives of your discussion section should include the following:

Reiterate the Research Problem/State the Major Findings Briefly reiterate the research problem you are investigating and explain why the subject of analysis around which you designed the case study were used. You should then describe the findings revealed from your study of the case using direct, declarative, and succinct proclamation of the study results. Highlight any findings that were unexpected or especially profound.

Explain the Meaning of the Findings and Why They are Important Systematically explain the meaning of your case study findings and why you believe they are important. Begin this part of the section by repeating what you consider to be your most important or surprising finding first, then systematically review each finding. Be sure to thoroughly extrapolate what your analysis of the case can tell the reader about situations or conditions beyond the actual case that was studied while, at the same time, being careful not to misconstrue or conflate a finding that undermines the external validity of your conclusions.

Relate the Findings to Similar Studies No study in the social sciences is so novel or possesses such a restricted focus that it has absolutely no relation to previously published research. The discussion section should relate your case study results to those found in other studies, particularly if questions raised from prior studies served as the motivation for choosing your subject of analysis. This is important because comparing and contrasting the findings of other studies helps support the overall importance of your results and it highlights how and in what ways your case study design and the subject of analysis differs from prior research about the topic.

Consider Alternative Explanations of the Findings Remember that the purpose of social science research is to discover and not to prove. When writing the discussion section, you should carefully consider all possible explanations revealed by the case study results, rather than just those that fit your hypothesis or prior assumptions and biases. Be alert to what the in-depth analysis of the case may reveal about the research problem, including offering a contrarian perspective to what scholars have stated in prior research if that is how the findings can be interpreted from your case.

Acknowledge the Study's Limitations You can state the study's limitations in the conclusion section of your paper but describing the limitations of your subject of analysis in the discussion section provides an opportunity to identify the limitations and explain why they are not significant. This part of the discussion section should also note any unanswered questions or issues your case study could not address. More detailed information about how to document any limitations to your research can be found here .

Suggest Areas for Further Research Although your case study may offer important insights about the research problem, there are likely additional questions related to the problem that remain unanswered or findings that unexpectedly revealed themselves as a result of your in-depth analysis of the case. Be sure that the recommendations for further research are linked to the research problem and that you explain why your recommendations are valid in other contexts and based on the original assumptions of your study.

V.  Conclusion

As with any research paper, you should summarize your conclusion in clear, simple language; emphasize how the findings from your case study differs from or supports prior research and why. Do not simply reiterate the discussion section. Provide a synthesis of key findings presented in the paper to show how these converge to address the research problem. If you haven't already done so in the discussion section, be sure to document the limitations of your case study and any need for further research.

The function of your paper's conclusion is to: 1) reiterate the main argument supported by the findings from your case study; 2) state clearly the context, background, and necessity of pursuing the research problem using a case study design in relation to an issue, controversy, or a gap found from reviewing the literature; and, 3) provide a place to persuasively and succinctly restate the significance of your research problem, given that the reader has now been presented with in-depth information about the topic.

Consider the following points to help ensure your conclusion is appropriate:

• If the argument or purpose of your paper is complex, you may need to summarize these points for your reader.
• If prior to your conclusion, you have not yet explained the significance of your findings or if you are proceeding inductively, use the conclusion of your paper to describe your main points and explain their significance.
• Move from a detailed to a general level of consideration of the case study's findings that returns the topic to the context provided by the introduction or within a new context that emerges from your case study findings.

Note that, depending on the discipline you are writing in or the preferences of your professor, the concluding paragraph may contain your final reflections on the evidence presented as it applies to practice or on the essay's central research problem. However, the nature of being introspective about the subject of analysis you have investigated will depend on whether you are explicitly asked to express your observations in this way.

Problems to Avoid

Overgeneralization One of the goals of a case study is to lay a foundation for understanding broader trends and issues applied to similar circumstances. However, be careful when drawing conclusions from your case study. They must be evidence-based and grounded in the results of the study; otherwise, it is merely speculation. Looking at a prior example, it would be incorrect to state that a factor in improving girls access to education in Azerbaijan and the policy implications this may have for improving access in other Muslim nations is due to girls access to social media if there is no documentary evidence from your case study to indicate this. There may be anecdotal evidence that retention rates were better for girls who were engaged with social media, but this observation would only point to the need for further research and would not be a definitive finding if this was not a part of your original research agenda.

Failure to Document Limitations No case is going to reveal all that needs to be understood about a research problem. Therefore, just as you have to clearly state the limitations of a general research study , you must describe the specific limitations inherent in the subject of analysis. For example, the case of studying how women conceptualize the need for water conservation in a village in Uganda could have limited application in other cultural contexts or in areas where fresh water from rivers or lakes is plentiful and, therefore, conservation is understood more in terms of managing access rather than preserving access to a scarce resource.

Failure to Extrapolate All Possible Implications Just as you don't want to over-generalize from your case study findings, you also have to be thorough in the consideration of all possible outcomes or recommendations derived from your findings. If you do not, your reader may question the validity of your analysis, particularly if you failed to document an obvious outcome from your case study research. For example, in the case of studying the accident at the railroad crossing to evaluate where and what types of warning signals should be located, you failed to take into consideration speed limit signage as well as warning signals. When designing your case study, be sure you have thoroughly addressed all aspects of the problem and do not leave gaps in your analysis that leave the reader questioning the results.

Case Studies. Writing@CSU. Colorado State University; Gerring, John. Case Study Research: Principles and Practices . New York: Cambridge University Press, 2007; Merriam, Sharan B. Qualitative Research and Case Study Applications in Education . Rev. ed. San Francisco, CA: Jossey-Bass, 1998; Miller, Lisa L. “The Use of Case Studies in Law and Social Science Research.” Annual Review of Law and Social Science 14 (2018): TBD; Mills, Albert J., Gabrielle Durepos, and Eiden Wiebe, editors. Encyclopedia of Case Study Research . Thousand Oaks, CA: SAGE Publications, 2010; Putney, LeAnn Grogan. "Case Study." In Encyclopedia of Research Design , Neil J. Salkind, editor. (Thousand Oaks, CA: SAGE Publications, 2010), pp. 116-120; Simons, Helen. Case Study Research in Practice . London: SAGE Publications, 2009;  Kratochwill,  Thomas R. and Joel R. Levin, editors. Single-Case Research Design and Analysis: New Development for Psychology and Education .  Hilldsale, NJ: Lawrence Erlbaum Associates, 1992; Swanborn, Peter G. Case Study Research: What, Why and How? London : SAGE, 2010; Yin, Robert K. Case Study Research: Design and Methods . 6th edition. Los Angeles, CA, SAGE Publications, 2014; Walo, Maree, Adrian Bull, and Helen Breen. “Achieving Economic Benefits at Local Events: A Case Study of a Local Sports Event.” Festival Management and Event Tourism 4 (1996): 95-106.

Writing Tip

At Least Five Misconceptions about Case Study Research

Social science case studies are often perceived as limited in their ability to create new knowledge because they are not randomly selected and findings cannot be generalized to larger populations. Flyvbjerg examines five misunderstandings about case study research and systematically "corrects" each one. To quote, these are:

Misunderstanding 1 :  General, theoretical [context-independent] knowledge is more valuable than concrete, practical [context-dependent] knowledge. Misunderstanding 2 :  One cannot generalize on the basis of an individual case; therefore, the case study cannot contribute to scientific development. Misunderstanding 3 :  The case study is most useful for generating hypotheses; that is, in the first stage of a total research process, whereas other methods are more suitable for hypotheses testing and theory building. Misunderstanding 4 :  The case study contains a bias toward verification, that is, a tendency to confirm the researcher’s preconceived notions. Misunderstanding 5 :  It is often difficult to summarize and develop general propositions and theories on the basis of specific case studies [p. 221].

While writing your paper, think introspectively about how you addressed these misconceptions because to do so can help you strengthen the validity and reliability of your research by clarifying issues of case selection, the testing and challenging of existing assumptions, the interpretation of key findings, and the summation of case outcomes. Think of a case study research paper as a complete, in-depth narrative about the specific properties and key characteristics of your subject of analysis applied to the research problem.

Flyvbjerg, Bent. “Five Misunderstandings About Case-Study Research.” Qualitative Inquiry 12 (April 2006): 219-245.

• << Previous: Writing a Case Analysis Paper
• Next: Writing a Field Report >>
• Last Updated: May 7, 2024 9:45 AM
• URL: https://libguides.usc.edu/writingguide/assignments

• Open access
• Published: 05 May 2024

The learning curve in endoscopic transsphenoidal skull-base surgery: a systematic review

• Abdulraheem Alomari 1 ,
• Mazin Alsarraj 2 &
• Sarah Alqarni 3  

BMC Surgery volume  24 , Article number:  135 ( 2024 ) Cite this article

156 Accesses

Metrics details

The endoscopic endonasal transsphenoidal approach (EETA) has revolutionized skull-base surgery; however, it is associated with a steep learning curve (LC), necessitating additional attention from surgeons to ensure patient safety and surgical efficacy. The current literature is constrained by the small sample sizes of studies and their observational nature. This systematic review aims to evaluate the literature and identify strengths and weaknesses related to the assessment of EETA-LC.

A systematic review was conducted following the PRISMA guidelines. PubMed and Google Scholar were searched for clinical studies on EETA-LC using detailed search strategies, including pertinent keywords and Medical Subject Headings. The selection criteria included studies comparing the outcomes of skull-base surgeries involving pure EETA in the early and late stages of surgeons’ experience, studies that assessed the learning curve of at least one surgical parameter, and articles published in English.

The systematic review identified 34 studies encompassing 5,648 patients published between 2002 and 2022, focusing on the EETA learning curve. Most studies were retrospective cohort designs (88%). Various patient assortment methods were noted, including group-based and case-based analyses. Statistical analyses included descriptive and comparative methods, along with regression analyses and curve modeling techniques. Pituitary adenoma (PA) being the most studied pathology (82%). Among the evaluated variables, improvements in outcomes across variables like EC, OT, postoperative CSF leak, and GTR. Overcoming the initial EETA learning curve was associated with sustained outcome improvements, with a median estimated case requirement of 32, ranging from 9 to 120 cases. These findings underscore the complexity of EETA-LC assessment and the importance of sustained outcome improvement as a marker of proficiency.

Conclusions

The review highlights the complexity of assessing the learning curve in EETA and underscores the need for standardized reporting and prospective studies to enhance the reliability of findings and guide clinical practice effectively.

Peer Review reports

With the advent of endoscopic techniques, skull-base surgery has significantly advanced. The modern history of neuro-endoscopy began in the early 1900s with an innovation by Lespinasse and Dandy, involving intraventricular endoscopy to coagulate the choroid plexus for treating communicating hydrocephalus [ 1 ]. In 1963, Guiot first reported an endoscopic approach via the transsphenoidal route as an adjunct to procedures performed under microscopy [ 2 , 3 ]. In 1992, Jankowski et al. described a purely endoscopic approach for pituitary adenoma resection [ 1 ].

The advantages of endoscopy have encouraged skull-base surgeons to adopt this technique, which provides a panoramic view of critical anatomical landmarks and improved access to the corners and deep surgical areas while inducing only minor trauma to the nasal structures, thereby enhancing postoperative patient comfort [ 4 ]. Compared with procedures involving microscopy, the endoscopic approach results in a shorter operating time (OT), a reduced hospitalization period, a lower rate of complications, and a higher endocrinological cure rate [ 5 , 6 ]. Despite these benefits, the endoscopic approach is hindered by a two-dimensional view, instrument interference, difficulties in achieving homeostasis, and a steep learning curve (LC) [ 4 ].

Since its inception, pioneers in the field have recognized the steep LC associated with the endoscopic technique [ 7 ]. The safety and efficacy of the endoscopic endonasal transsphenoidal approach (EETA), as an alternative to the gold-standard microscopic technique, have been established. However, the steep LC associated with the endoscopic approach may affect short-term outcomes post-procedure [ 5 , 6 ]. Additionally, as the skull-base endoscopic technique constantly evolves and expands, a thorough understanding of the associated LC is critical.

The results of existing publications on the EETA-LC are challenging to interpret due to small sample sizes, observational study designs, and a lack of standardization in assessment methodologies. In this systematic review aims to elucidate the EETA-LC from the literature by addressing the following questions: How was EETA LC evaluated? Which set of variables was used to assess the LC? What is the influence of the LC on the examined variables?

A systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines [ 8 ]. The review was registered on PROSPERO (CRD42023494731). We searched different databases for articles that assessed the learning curve of EETA without date restriction (PubMed, and Google Scholar). We used a particular equation for each database using a combination of the following keywords and Medical Subject Headings: (Endoscopy OR endoscopic skull base OR endoscopic endonasal transsphenoidal approach) AND (Skull Base Neoplasms OR Pituitary OR pituitary adenoma) AND (Learning Curve OR endoscopic learning curve OR surgical learning curve).

First, two authors (AA, MA) independently screened the titles and abstracts of articles in the databases for learning curve analysis of EETA, either for a single surgeon or a team, by directly comparing outcomes between early and late cases performed. The full texts of the relevant articles were reviewed. When there was a disagreement, the articles were thoroughly discussed before their inclusion in the review. The bibliographies of the selected studies were also screened for relevant citations, which turned up studies that were already selected from the database search.

Studies were included according to the following inclusion criteria: 1) Comparison of outcomes between initial and advanced experiences with the endonasal endoscopic transsphenoidal approach to treat skull-base pathology, defined as "early experience" and "late experience," respectively; 2) Assessment of at least one parameter based on early and late experiences; 3) Randomized controlled trials, prospective cohort studies, retrospective cohort studies, case–control studies, and case series studies were included; and 4) English-language publications.

The study’s exclusion criteria included the following: 1) Studies not performing learning curve analysis; 2) Studies comparing the outcomes of microscopic and endoscopic transsphenoidal approaches without providing separate data for the endoscopic approach; 3) Studies comparing the learning curve between two EETA techniques, using simulated models or questionnaire-based analysis; 4) Studies comparing the microscopic vs. endoscopic approach without separate data available specifically for the endoscopic arm. Additionally, case reports, reviews, animal studies, technical notes, comments, and correspondence were excluded.

Data collection and analysis

The following data were extracted directly from the articles: 1) author names; 2) the year of publication; 3) Time interval of performed procedures; 4) study design; 5) the sample size; 6) techniques used for learning curve analysis (methods used to assort the patients for the analysis); (conducting statistical analysis vs. simple comparison of outcomes); 7) the sample size in each study arm when group splitting performed (early experience vs. late experience); 8) detailed information about surgeon experience at the time of LC assessment (including or omitting the first few EETA cases); 9) single vs. multiple pathologies; 10) team vs. single-surgeon experiences; 11) evaluated set of variables; 12) Variables that improved with experience; and 13) the number of cases required to overcome the initial LC or other methods to identify overcoming the learning curve.

Study quality assessment and risk of bias

Two reviewers conducted a quality assessment and evaluated the risk of bias in the included articles. We utilized the Newcastle–Ottawa Scale (NOS) [ 9 ] and the GRADE system [ 10 ].

Heterogeneity Analysis: Due to substantial heterogeneity observed among the included studies, which encompassed variations in study design, included pathologies, and outcome measures, a formal meta-analysis was not feasible. Therefore, we opted for a qualitative synthesis instead of a formal meta-analysis. Heterogeneity analysis and sensitivity analyses were not explicitly conducted.

Based on the inclusion and exclusion criteria, a total of 34 studies were identified (6 articles excluded after reviewing the full articles), including 5,648 patients [ 7 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 ] (Fig.  1 ). The included studies were published between 2002 and 2022, and the evaluated procedures were performed between 1990 and 2018. The majority of the included articles comprised retrospective cohort studies (88%), with two being prospective studies, and two articles presenting data from both prospective and retrospective study designs. Assessing a surgical learning curve involves various methods and techniques documented within the included articles. We observed various methods for patient assortment in conducting learning curve analyses across the literature, with group-based learning curve analysis noticeable in a significant proportion of articles (68%). Within these studies, there was an unclear rationale behind patient grouping. Nonetheless, patients were categorized into either equal group, segmented based on arbitrary time periods, or separated based on improvements in outcomes observed retrospectively after data analysis. Eleven articles (32%) utilize case-based analysis, where individual surgical cases serve as distinct data points, and their outcomes are monitored over time.

PRISMA flow diagram. PRISMA, Preferred Reporting Items for Systematic Reviews and Meta-Analyses

* The bibliographies of the selected studies were also screened for relevant citations which turned up studies already included from databases search

Our systematic review encompasses a wide range of statistical tests employed in the included studies to analyze various data types and address multifaceted research inquiries. The primary statistical methodologies utilized encompass descriptive statistical analysis, which includes metrics such as mean, median, frequency, and standard deviation, along with comparative statistical analysis, which includes techniques such as Chi-square analysis, analysis of variance (ANOVA), and t-tests. Descriptive statistical analysis alone was evident in 10 articles (29%), whereas comparative statistical analysis was present in 24 articles (71%). Noteworthy examples include Leach et al. [ 16 ], who conducted analysis of variance (ANOVA) with post hoc Bonferroni tests for parametric data, Chi-Square Test, or Mann–Whitney tests for nonparametric data, and regression analysis to explore the relationship between surgical duration and relevant factors. Smeth et al. [ 17 ] undertook analyses using chi-square, Fisher exact, Student t-test, Mann–Whitney U test, and analysis of variance, aligning with their examination of categorical and continuous variables across distinct groups. Similarly, Sonnenburg et al. [ 12 ] applied a one-way ANOVA to discern variations between groups, highlighting the importance of understanding differences in means across categorical variables or treatment cohorts.

Regression analyses, scatterplots, McNemar tests, ROC curve analysis, and logistic regression models were integral across various studies, serving multiple purposes. Regression analyses, such as linear regression models, facilitated the exploration of intricate relationships among variables like age, tumor size, and surgical duration, identifying potential risk factors in surgical contexts [ 22 ]. Scatterplots visually depicted these relationships, offering intuitive insights into temporal variations, notably in the examination of surgery date versus duration [ 22 ]. McNemar tests were instrumental in evaluating changes in hormone levels, crucial for understanding postoperative outcomes and hormonal dynamics [ 37 ]. Additionally, ROC curve analysis provided a robust method for determining the level of surgical experience necessary to achieve gross total resection (GTR), offering actionable insights into surgical proficiency and patient outcomes [ 37 ]. Binary logistic regression models were utilized to identify prognostic factors contributing to the attainment of Gross Total Resection (GTR), hormonal recuperation, and visual restoration. For instance, variables such as surgical experience (≤ 100 vs. > 100 cases) were examined within this analytical framework [ 37 ].

In our examination of the included articles, we noted a lack of thorough description regarding the experience of surgeons or surgical teams with the endoscopic endonasal transsphenoidal approach (EETA), the extent of the approach undertaken, and the level of involvement of individual surgeons or surgical teams during procedures. Thirteen articles (38%) reported including the initial cases of EETA, which may indicate a lack of prior experience with the approach. Additionally, seven articles (21%) detailed the experience of a single surgeon, while the majority (79%) evaluated team experiences. There was a wide range of pathologies included in all the studies. Twenty articles (59%) focused on a single pathology, while fourteen studies (41%) examined multiple pathologies. Pituitary adenoma (PA) was the most frequently reported pathology (82%), followed by craniopharyngioma (CP) (44%). Three studies assessed the learning curve of cerebrospinal fluid (CSF) leak repair following treatment of multiple pathologies. Descriptions of the surgical approach, particularly distinguishing between simple and extended techniques, were notably lacking across all articles. However, seventeen articles (50%) did mention pathologies that often require an extended approach, such as meningioma, chordoma, and CP. A number of studies have investigated the variations in tumor type and size among the examined groups, particularly between early and late groups. Notably, findings from studies such as [ 7 , 16 , 17 , 22 , 23 , 26 , 38 ] indicated that no statistical differences were observed between these groups. The characteristics of the included studies [ 7 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 ] are summarized in Table  1 .

The EETA-LC was evaluated based on a diverse set of variables. The most frequently analyzed variables were postoperative cerebrospinal fluid (CSF) leak in 28 articles (82%) [ 7 , 12 , 13 , 15 , 16 , 17 , 19 , 20 , 21 , 22 , 23 , 25 , 27 , 28 , 29 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 ], gross total resection (GTR) in 21 articles (62%) [ 7 , 13 , 14 , 16 , 19 , 21 , 22 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 36 , 37 , 38 , 39 , 40 ], post operative diabetes insipidus (DI) in 15 articles (44%) [ 12 , 13 , 16 , 17 , 19 , 21 , 22 , 29 , 30 , 31 , 32 , 34 , 36 , 37 , 41 ], operative time (OT) in 12 articles (35%) [ 7 , 13 , 14 , 16 , 17 , 22 , 29 , 32 , 34 , 35 , 36 , 38 ] and visual improvement in 12 articles (35%) [ 13 , 14 , 16 , 21 , 22 , 28 , 31 , 32 , 34 , 36 , 37 , 41 ]. (Fig.  2 ).

Frequency at which certain variables were evaluated in the literature to assess the EETA learning curve. EETA, endoscopic endonasal transsphenoidal approach; post-op, postoperative; CSF, cerebrospinal fluid; GTR, gross total resection; DI, diabetes insipidus; LOS, length of stay; IOP, intraoperative; ICA, internal carotid artery; SIADH, syndrome of inappropriate antidiuretic hormone secretion; LD, lumbar drain; CNS, central nervous system; CN, cranial nerve; EBL, estimated blood loss; DVT, deep vein thrombosis

In all the studies included, improvements were observed between early and late-experience stages [ 7 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 ]. Among the evaluated variables, the following improvements were noted: the endocrinological cure rate (EC) showed improvement in all 7 articles out of 7 evaluated [ 13 , 16 , 18 , 21 , 24 , 30 , 33 ], operative time (OT) improved in 11 out of 12 articles (91%) [ 13 , 14 , 16 , 17 , 22 , 29 , 32 , 34 , 35 , 36 , 38 ], postoperative cerebrospinal fluid leak (CSF) improved in 23 out of 28 articles (82%) [ 12 , 15 , 17 , 19 , 20 , 22 , 23 , 25 , 27 , 28 , 29 , 31 , 32 , 33 , 34 , 35 , 37 , 38 , 39 , 40 , 41 , 42 , 43 ], visual improvement was observed in 9 out of 12 articles (75%) [ 13 , 14 , 16 , 22 , 28 , 31 , 34 , 37 , 41 ], gross total resection (GTR) improved in 14 out of 21 articles (67%) [ 7 , 13 , 14 , 19 , 21 , 22 , 26 , 27 , 28 , 29 , 30 , 38 , 39 , 40 ], hospital length of stay (LOS) decreased in five out of 10 studies (50%) [ 11 , 12 , 16 , 17 , 22 ], and postoperative diabetes insipidus (DI) decreased in 7 out of 15 articles (47%) [ 3 , 14 , 16 , 17 , 21 , 22 , 33 ] (Fig.  3 ).

Proportion of main improved variables with experiences. EC, Endocrinological cure; OT, Operative time; post-op: postoperative; CSF, cerebrospinal fluid; GTR, gross total resection; hLOS, hospital length of stay; DI, diabetes insipidus

Moreover, 12 articles (35%) reported both significant and non-significant improvements in outcomes [ 7 , 13 , 14 , 16 , 17 , 21 , 22 , 31 , 32 , 34 , 38 , 41 ]. In 10 studies (29%), solely a trend of improvement was observed [ 11 , 15 , 19 , 20 , 23 , 26 , 27 , 29 , 30 , 40 ], while 8 articles (23%) reported solely significant improvements [ 18 , 24 , 25 , 35 , 36 , 37 , 42 , 43 ]. However, in four studies, despite observing a tendency towards better outcomes, no statistical disparities were identified among all assessed variables [ 12 , 28 , 33 , 39 ]. None of the included studies reported a deterioration in any of the assessed outcomes over time, except for one study where a significant decline in GTR was observed in the late group [ 33 ]. This decline was attributed to the inclusion of more invasive and complex tumors in the late group. Nevertheless, Younus et al. documented ongoing improvement in GTR even after surpassing the initial learning curve [ 7 ].

In this systematic review, the primary technique employed to determine the transition point indicating the overcoming of the initial learning curve involved observing sustained and consistent improvement in outcomes over time. In almost half of the included articles, overcoming the initial learning curve (observing improvement of outcomes) was linked to the number of cases performed. Out of the 34 analyzed studies, 16 (47%) estimated the number of cases needed to overcome the initial learning curve of EETA. Reported cases ranged widely from 9 to 120, with a mode of 50. Considering both the median and the Interquartile Range (IQR) provides a comprehensive understanding of the reported case distribution and central tendency for overcoming the initial EETA learning curve. The median number of cases needed is 32, with an IQR of 20. These numbers are estimates and require careful interpretation [ 16 , 17 , 20 , 21 , 22 , 23 , 24 , 25 , 29 , 31 , 32 , 33 , 35 , 36 , 37 , 38 , 42 ].

Regarding the quality of included studies, the NOS quality assessment scale was used. 21 studies graded as fair quality while the remaining 13 articles rated as poor quality [ 9 ]. The risk of bias was evaluated according to the GRADE system. All included studies are observational cohort study and graded either as low or very low grade [ 10 ]. This reflects the great heterogeneity and high risk of bias due to the study design of the current EETA-LC literature.

Endoscopic techniques have drastically improved skull-base surgery. Unlike procedures involving a microscope, many neurosurgeons have acquired experience in endoscopic techniques later in their careers, and the level of exposure to these techniques during training years has varied among surgeons. The LC is a critical factor in the acquisition of new surgical skills. Understanding the link between the EETA-LC and surgical outcomes will enable surgeons to better understand what to expect and what measures to apply as those surgical skills develop. Many studies in other surgical domains have reported on the LC during the acquisition of new surgical techniques [ 44 , 45 , 46 , 47 ]. Most minimally invasive surgeries are associated with a challenging LC, and EETA is no exception [ 7 , 46 ].

The concept of the LC was first established in the field of aircraft manufacturing and refers to an improvement in performance over time [ 48 ]. Smith et al. [ 17 ] have defined it as the number of procedures that must be performed for the outcomes to approach a long-term mean rate. Typically, an LC is characterized by an S-shaped curve with three stages: an early phase, during which new skill sets are acquired; a middle phase, in which the speed of learning rapidly increases; and an expert phase in which the performance reaches a plateau [ 49 ]. However, other curves have been proposed that involve a dip in the LC following the initial acceleration of the learning rate; this occurs especially with handling more challenging cases. Another potential decline may emerge after a long period of experience. Despite having reached a plateau in the learning curve after an extended period, declines in manual dexterity, eyesight, memory, and cognition may overshadow the benefits of accumulated experience, leading to diminished performance levels [ 50 ].

The absence of consensus on the best applicable methods to describe and assess the learning curve may explain the diversity of analysis methods observed in this systematic review. In their large systematic review regarding learning curve assessment in healthcare technologies, Ramsay et al. [ 51 ] reported that group splitting was the most frequent method. They defined group splitting as dividing the data by experience levels and conducting testing on discrete groups, often halves or thirds. The statistical methods applied included t-tests, chi-squared tests, Mann–Whitney U tests, and simple ANOVA.

In our review, we reached a similar conclusion. We observed that a substantial portion of articles (68%) utilized group-based learning curve analysis [ 7 , 11 , 12 , 13 , 16 , 17 , 19 , 21 , 22 , 23 , 26 , 27 , 28 , 30 , 31 , 32 , 33 , 34 , 36 , 37 , 38 , 42 , 43 ]. Additionally, we similarly noted that papers frequently lacked explanations for the selection of cut points, raising concerns about potential bias resulting from data-dependent splitting. It is important to acknowledge that this method of group categorization has inherent drawbacks, including challenges related to small sample sizes, the use of arbitrary cutoff points, and the inability to eliminate all potential confounding variables [ 52 ].

Descriptive analysis was found in 10 articles (29%) within this review [ 11 , 15 , 19 , 20 , 23 , 26 , 27 , 29 , 30 , 40 ]. While providing an initial grasp of data distribution and characteristics, descriptive analysis may fall short in capturing the intricate dynamics of the learning curve over time or the factors affecting its impact [ 51 ]. Alternatively, conducting rigorous statistical analyses afterward offers better insight and interpretation of the results. This approach aims to mitigate the influence of confounding factors on outcome assessments over time [ 51 , 52 ].

In our review, 24 articles (71%) conducted a wide variety of statistical analyses [ 7 , 12 , 13 , 14 , 16 , 17 , 18 , 21 , 22 , 24 , 25 , 28 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 41 , 42 , 43 ], including but not limited to the following tests: Chi-square Test, Fischer exact test, Student's t-test, Analysis of Variance (ANOVA), Mann–Whitney U Test, McNemar tests, Multivariate linear regression model, Cumulative Sum (CUSUM), and ROC Curve Analysis [ 13 , 16 , 22 , 32 , 37 , 38 , 39 ]. Four studies indicated that there was no statistically significant difference observed among the variables under evaluation. The lack of significance was attributed to several factors including small sample sizes, meticulous case selection, involvement of an otolaryngology team throughout the procedure, an increase in the number of invasive tumors in the late-experience study group, previous surgical experience, intensive training, level of supervision, and gradual inclusion of residents [ 12 , 28 , 33 , 39 ]. These efforts should be regarded as beneficial strategies aimed at reducing the steepness of the EETA learning curve.

To obtain more accurate results, it is crucial to eliminate confounding factors, such as the level of supervision, prior experience, the heterogeneity of cases being treated, and their complexity when evaluating the LC. Thus, it is essential to incorporate multivariate logistic regression analysis to mitigate the impact of these potential confounding factors [ 51 ]. Chi et al. [ 22 ] divided their patients into equal groups of 40 cases each. They then compared potential confounding variables to minimize their influence on learning curve assessment. This comparison includes demographic and clinical factors between the two groups, such as sex distribution, mean age, tumor size (microadenomas vs. macroadenomas), visual field defects, and tumor types (non-functioning, functioning adenomas, etc.). By conducting these comparisons, the researchers sought to identify discrepancies in demographic and clinical features between the groups.

The description of a surgeon's extensive prior experience is crucial for accurately quantifying the assessment of the learning curve, a point reported to be neglected during the assessment in various types of learning assessments related to healthcare procedures [ 49 ]. In our review, we observed the same conclusion in all included studies. However, the inclusion of the initial first few cases was mentioned in 13 (38%) articles, which might be used as a surrogate for no prior experience with EETA. Furthermore, five articles did not include the initial few cases. Among these, four studies examined the learning curve of more complex cases such as meningioma, craniopharyngioma, and growth hormone pituitary adenoma, employing an extended approach. Conversely, Younus et al. [ 7 ] deliberately excluded these cases to assess various stages of the learning curve.

Assessing multiple pathologies with varying complexities could significantly impact learning curve assessments. In our review, 59% of articles focused on a single pathology, while 41% explored multiple pathologies. Pituitary adenoma (PA) was the most evaluated (82%), followed by craniopharyngioma (CP) (44%). Controlling confounding variables like tumor type and size may yield more reliable results. Some studies used statistical analyses to compare early and late cases, while others relied on descriptive analyses. Shou et al. noted a drop in GTR over time due to late involvement of complex cases [ 33 ]. Conversely, studies analyzing tumor size and type found GTR improvement with experience [ 7 , 23 ]. Thorough multivariable analysis of confounding factors is crucial for representative LC analysis.

The LC is often assessed based on two main categories of variables: those related to the surgical procedure (OT, estimated blood loss, and extent of resection) and those related to patient outcomes (duration of hospitalization, the incidence of complications, and the mortality rate) [ 50 ]. In this systematic review, OT was one of the most frequent parameters that significantly reduced as one gained experience. Although OT is commonly utilized as an outcome measure, it is only a surrogate means of evaluating the LC and may not always accurately represent patient outcomes [ 52 ]. Another point to consider is the lack of standardized variables for assessing the LC, and the included studies evaluated more than 45 distinct variables. Khan et al. highlighted the importance of using consistent variable definitions across studies to derive accurate conclusions from aggregated LC data [ 52 ].

A dynamic relationship exists between surgical outcomes and the LC, and each phase of the LC influences a distinct set of variables differently. One study, which included data from 1,000 EETA cases after purposely eliminating the first 200 cases, showed that variables such as GTR and the endocrinological cure rate continued to improve after the first 200 cases, whereas other parameters remained unchanged. Authors concluded that some variables will continue to improve after passing the initial LC phase [ 7 ]. Determining the precise number of cases needed to surpass the initial learning curve (LC) has proven challenging. Shikary et al. observed a notable decrease in postoperative CSF leaks after 100 surgeries, while a reduction in operative time was evident after 120 cases [ 35 ]. However, specifying a definitive number to overcome the learning curve of the Endoscopic Endonasal Transsphenoidal Approach (EETA) remains challenging due to individual variability, diverse pathologies, and evolving surgical techniques.

Assessing the learning curve of the Endoscopic Endonasal Transsphenoidal Approach (EETA-LC) faces notable challenges due to its intricate techniques and the wide array of pathologies it addresses. The diversity across specialties makes standardizing studies difficult. To understand the dynamic learning process in EETA-LC, influenced by individual surgeon skill, patient nuances, and procedural complexities, longitudinal studies and advanced analytical methods are essential. Moreover, the complexity of statistical analysis adds another layer of challenge, highlighting the necessity for interdisciplinary collaboration and innovative methodologies.

To address the current limitations in the literature regarding the EETA LC, we propose several key strategies for future studies. Firstly, we advocate for multicenter collaboration, coupled with standardized processes, to comprehensively assess the EETA LC. This collaborative approach will facilitate the aggregation of data from diverse surgical settings, enhancing the generalizability of findings and minimizing bias. Furthermore, rigorous documentation of the previous and current experience of involved surgeons is paramount. We suggest categorizing surgeons based on their levels of experience to accurately elucidate the impact of proficiency on surgical outcomes. Secondly, given the wide variety of complexities of skull base pathologies encountered, we recommend further categorization of cases based on their levels of complexity. This stratification will enable a more nuanced analysis of the learning curve across different levels of surgical challenge. Thirdly, standardization of outcome measures used to assess the learning curve is imperative, with specific definitions provided for each outcome. This ensures consistency and comparability across studies, facilitating meaningful interpretation of results. Finally, conducting prospective study designs with sufficient follow-up periods, along with rigorous multivariate statistical analyses among these categorized groups, is essential to mitigate the influence of confounding variables and strengthen the validity of findings. Implementing these strategies will help future studies to overcome the current limitations in the literature, leading to a deeper understanding of the EETA learning curve and ultimately improving patient outcomes.

This systematic review identified 34 studies that reported a relationship between improvements in surgical outcomes and a surgeon’s level of experience with EETA. There is notable significant heterogeneity in the current literature on EETA-LC regarding the techniques used to assess the LC, variables assessed, types of pathology included, and insufficient reporting of the surgeon or team's current and previous experience with EETA. The main variables improved with experience were EC, postoperative CSF leak, OT, GTR visual improvement, and hospital LOS. Future studies with multicenter collaboration and standardized processes for assessing the EETA LC will enhance generalizability and minimize bias. Rigorous documentation of surgeons' experience levels, categorization of cases by complexity, and standardized outcome measures are essential. Additionally, rigorous statistical analyses will strengthen validity and mitigate confounding variables. Implementing these strategies will deepen our understanding of the EETA learning curve, ultimately leading to improved patient outcomes.

Availability of data and materials

The datasets used and/or analysed during the current study are available from the corresponding author on reasonable request.

Abbreviations

Endoscopic endonasal transsphenoidal approach

• Learning curve

Cerebrospinal fluid

Diabetes insipidus

Gross total resection

Cappabianca P, de Divitiis E. Endoscopy and transsphenoidal surgery. Neurosurgery. 2004;54:1043–50.

Article   PubMed   Google Scholar  

Gandhi CD, Post KD. Historical movements in transsphenoidal surgery. Neurosurg Focus. 2001;11:1–4.

Article   Google Scholar  

Gandhi CD, Christiano LD, Eloy JA, Prestigiacomo CJ, Post KD. The historical evolution of transsphenoidal surgery: facilitation by technological advances. Neurosurg Focus. 2009;27:E8.

de Divitiis E. Endoscopic transsphenoidal surgery: stone-in-the-pond effect. Neurosurgery. 2006;59:512–20.

Rotenberg B, Tam S, Ryu WHA, Duggal N. Microscopic versus endoscopic pituitary surgery: a systematic review. Laryngoscope. 2010;120:1292–7.

Tabaee A, Anand VK, Barrón Y, Hiltzik DH, Brown SM, Kacker A, et al. Endoscopic pituitary surgery: a systematic review and meta-analysis. J Neurosurg. 2009;111:545–54.

Younus I, Gerges MM, Uribe-Cardenas R, Morgenstern PF, Eljalby M, Tabaee A, et al. How long is the tail end of the learning curve? Results from 1000 consecutive endoscopic endonasal skull base cases following the initial 200 cases. J Neurosurg. 2020;134:750–60.

Page MJ, McKenzie JE, Bossuyt PM, Boutron I, Hoffmann TC, Mulrow CD, et al. The PRISMA 2020 statement: an updated guideline for reporting systematic reviews. Int J Surg. 2021;88:105906.

Wells G, Shea B, O'Connell D, Peterson J, Welch V, Losos M, Tugwell P. The Newcastle-Ottawa Scale (NOS) for assessing the quality of nonrandomised studies in meta-analyses. 2013. Retrieved from http://www.ohri.ca/programs/clinical_epidemiology/oxford.asp .

Balshem H, Helfand M, Schünemann HJ, Oxman AD, Kunz R, Brozek J, Vist GE, Falck-Ytter Y, Meerpohl J, Norris S, Guyatt GH. GRADE guidelines: 3. Rating the quality of evidence. J Clin Epidemiol. 2011;64(4):401–6. https://doi.org/10.1016/j.jclinepi.2010.07.015 .

Cappabianca P, Cavallo L, Colao A, Del Basso De Caro M, Esposito F, Cirillo S, et al. Endoscopic endonasal transsphenoidal approach: outcome analysis of 100 consecutive procedures. Minim Invasive Neurosurg. 2002;45:193–200.

Article   CAS   PubMed   Google Scholar  

Sonnenburg RE, White D, Ewend MG, Senior B. The learning curve in minimally invasive pituitary surgery. Am J Rhinol. 2004;18:259–63.

Kenan K, İhsan A, Dilek O, Burak C, Gurkan K, Savas C. The learning curve in endoscopic pituitary surgery and our experience. Neurosurg Rev. 2006;29:298–305.

Yano S, Kawano T, Kudo M, Makino K, Nakamura H, Kai Y, et al. Endoscopic endonasal transsphenoidal approach through the bilateral nostrils for pituitary adenomas. Neurol Med Chir (Tokyo). 2009;49:1–7.

Gondim JA, Schops M, de Almeida JPC, de Albuquerque LAF, Gomes E, Ferraz T, et al. Endoscopic endonasal transsphenoidal surgery: surgical results of 228 pituitary adenomas treated in a pituitary center. Pituitary. 2010;13:68–77.

Leach P, Abou-Zeid AH, Kearney T, Davis J, Trainer PJ, Gnanalingham KK. Endoscopic transsphenoidal pituitary surgery: evidence of an operative learning curve. Neurosurgery. 2010;67:1205–12.

Smith SJ, Eralil G, Woon K, Sama A, Dow G, Robertson I. Light at the end of the tunnel: the learning curve associated with endoscopic transsphenoidal skull base surgery. Skull Base. 2010;20:69–74.

Article   PubMed   PubMed Central   Google Scholar  

Wagenmakers MAE, Netea-Maier RT, van Lindert EJ, Pieters GF, Grotenhuis AJ, Hermus AR. Results of endoscopic transsphenoidal pituitary surgery in 40 patients with a growth hormone-secreting macroadenoma. Acta Neurochir (Wien). 2011;153:1391–9.

Kumar S, Darr A, Hobbs C, Carlin W. Endoscopic, endonasal, trans-sphenoidal hypophysectomy: retrospective analysis of 171 procedures. J Laryngol Otol. 2012;126:1033–40.

Snyderman CH, Pant H, Kassam AB, Carrau RL, Prevedello DM, Gardner PA. The learning curve for endonasal surgery of the cranial base: A systematic approach to training. In: Kassam AB, Gardner PA, editors. Endoscopic approaches to the skull base. Ettlingen: Karger Publishers; 2012. p. 222–31.

Chapter   Google Scholar  

Bokhari AR, Davies MA, Diamond T. Endoscopic transsphenoidal pituitary surgery: a single surgeon experience and the learning curve. Br J Neurosurg. 2013;27:449.

Chi F, Wang Y, Lin Y, Ge J, Qiu Y, Guo L. A learning curve of endoscopic transsphenoidal surgery for pituitary adenoma. J Craniofac Surg. 2013;24:2064–7.

de los Santos G, Fragola C, Del Castillo R, Rodríguez V, D’oleo C, Reyes P. Endoscopic approaches to pituitary lesions: difficulties and challenges. Acta Otorrinolaringol Esp. 2013;64(258):64.

Google Scholar  

Hazer DB, Işık S, Berker D, Güler S, Gürlek A, Yücel T, et al. Treatment of acromegaly by endoscopic transsphenoidal surgery: surgical experience in 214 cases and cure rates according to current consensus criteria. J Neurosurg. 2013;119:1467–77.

Jakimovski D, Bonci G, Attia M, Shao H, Hofstetter C, Tsiouris AJ, et al. Incidence and significance of intraoperative cerebrospinal fluid leak in endoscopic pituitary surgery using intrathecal fluorescein. World Neurosurg. 2014;82:e513–23.

Koutourousiou M, Fernandez-Miranda JC, Wang EW, Snyderman CH, Gardner PA. Endoscopic endonasal surgery for olfactory groove meningiomas: outcomes and limitations in 50 patients. Neurosurg Focus. 2014;37:E8.

Mascarenhas L, Moshel YA, Bayad F, Szentirmai O, Salek AA, Leng LZ, et al. The transplanum transtuberculum approaches for suprasellar and sellar-suprasellar lesions: avoidance of cerebrospinal fluid leak and lessons learned. World Neurosurg. 2014;82:186–95.

Ottenhausen M, Banu MA, Placantonakis DG, Tsiouris AJ, Khan OH, Anand VK, et al. Endoscopic endonasal resection of suprasellar meningiomas: the importance of case selection and experience in determining extent of resection, visual improvement, and complications. World Neurosurg. 2014;82:442–9.

Ananth G, Hosmath AV, Varadaraju DN, Patil SR, Usman MM, Patil RP, et al. Learning curve in endoscopic transnasal sellar region surgery. J Evid Based Med Healthc. 2016;3:3166–72.

Jang JH, Kim KH, Lee YM, Kim JS, Kim YZ. Surgical results of pure endoscopic endonasal transsphenoidal surgery for 331 pituitary adenomas: a 15-year experience from a single institution. World Neurosurg. 2016;96:545–55.

Kshettry VR, Do H, Elshazly K, Farrell CJ, Nyquist G, Rosen M, et al. The learning curve in endoscopic endonasal resection of craniopharyngiomas. Neurosurg Focus. 2016;41:E9.

Qureshi T, Chaus F, Fogg L, Dasgupta M, Straus D, Byrne RW. Learning curve for the transsphenoidal endoscopic endonasal approach to pituitary tumors. Br J Neurosurg. 2016;30:637–42.

Shou X, Shen M, Zhang Q, Zhang Y, He W, Ma Z, et al. Endoscopic endonasal pituitary adenomas surgery: the surgical experience of 178 consecutive patients and learning curve of two neurosurgeons. BMC Neurol. 2016;16:1–8.

Ding H, Gu Y, Zhang X, Xie T, Liu T, Hu F, et al. Learning curve for the endoscopic endonasal approach for suprasellar craniopharyngiomas. J Clin Neurosci. 2017;42:209–16.

Shikary T, Andaluz N, Meinzen-Derr J, Edwards C, Theodosopoulos P, Zimmer LA. Operative learning curve after transition to endoscopic transsphenoidal pituitary surgery. World Neurosurg. 2017;102:608–12.

Eseonu CI, ReFaey K, Pamias-Portalatin E, Asensio J, Garcia O, Boahene KD, et al. Three-hand endoscopic endonasal transsphenoidal surgery: experience with an anatomy-preserving mononostril approach technique. Oper Neurosurg (Hagerstown). 2018;14:158–65.

Kim JH, Lee JH, Lee JH, Hong AR, Kim YJ, Kim YH. Endoscopic transsphenoidal surgery outcomes in 331 nonfunctioning pituitary adenoma cases after a single surgeon learning curve. World Neurosurg. 2018;109:e409–16.

Lofrese G, Vigo V, Rigante M, Grieco DL, Maresca M, Anile C, et al. Learning curve of endoscopic pituitary surgery: experience of a neurosurgery/ENT collaboration. J Clin Neurosci. 2018;47:299–303.

Robins JM, Alavi SA, Tyagi AK, Nix PA, Wilson TM, Phillips NI. The learning curve for endoscopic trans-sphenoidal resection of pituitary macroadenomas. A single institution experience, Leeds, UK. Acta Neurochir (Wien). 2018;160:39–47.

Algattas H, Setty P, Goldschmidt E, Wang EW, Tyler-Kabara EC, Snyderman CH, et al. Endoscopic endonasal approach for craniopharyngiomas with intraventricular extension: case series, long-term outcomes, and review. World Neurosurg. 2020;144:e447–59.

Soliman MA, Eaton S, Quint E, Alkhamees AF, Shahab S, O’Connor A, et al. Challenges, learning curve, and safety of endoscopic endonasal surgery of sellar-suprasellar lesions in a community hospital. World Neurosurg. 2020;138:e940–54.

Nix P, Alavi SA, Tyagi A, Phillips N. Endoscopic repair of the anterior skull base-is there a learning curve? Br J Neurosurg. 2018;32:407–11.

Park W, Nam D-H, Kong D-S, Lee KE, Park SI, Kim HY, et al. Learning curve and technical nuances of endoscopic skull base reconstruction with nasoseptal flap to control high-flow cerebrospinal fluid leakage: reconstruction after endoscopic skull base surgery other than pituitary surgery. Eur Arch Otorhinolaryngol. 2022;279:1335–40.

Lubowitz JH, Sahasrabudhe A, Appleby D. Minimally invasive surgery in total knee arthroplasty: the learning curve. Orthopedics. 2007;30:80.

PubMed   Google Scholar  

Hoppe DJ, Simunovic N, Bhandari M, Safran MR, Larson CM, Ayeni OR. The learning curve for hip arthroscopy: a systematic review. Arthroscopy. 2014;30:389–97.

Sclafani JA, Kim CW. Complications associated with the initial learning curve of minimally invasive spine surgery: a systematic review. Clin Orthop Relat Res. 2014;472:1711–7.

Pernar LI, Robertson FC, Tavakkoli A, Sheu EG, Brooks DC, Smink DS. An appraisal of the learning curve in robotic general surgery. Surg Endosc. 2017;31:4583–96.

Wright TP. Factors affecting the cost of airplanes. J Aeronaut Sci. 1936;3:122–8.

Cook JA, Ramsay CR, Fayers P. Using the literature to quantify the learning curve: a case study. Int J Technol Assess Health Care. 2007;23:255–60.

Hopper A, Jamison M, Lewis W. Learning curves in surgical practice. Postgrad Med J. 2007;83:777–9.

Article   CAS   PubMed   PubMed Central   Google Scholar  

Ramsay CR, Grant AM, Wallace SA, Garthwaite PH, Monk AF, Russell IT. Assessment of the learning curve in health technologies: a systematic review. Int J Technol Assess Health Care. 2000;16:1095–108.

Khan N, Abboudi H, Khan MS, Dasgupta P, Ahmed K. Measuring the surgical ‘learning curve’: methods, variables and competency. BJU Int. 2014;113:504–8.

Download references

Acknowledgements

Not applicable

No funding was received for this study.

Author information

Authors and affiliations.

Neurosurgery Department, East Jeddah Hospital, 2277 King Abdullah Rd, Al Sulaymaniyah, 22253, Jeddah, Saudi Arabia

Abdulraheem Alomari

Otolaryngology and Head and Neck Surgery Department, King Abdullah Medical Complex, Prince Nayef Street, Northern Abhor, 23816, Jeddah, Saudi Arabia

Mazin Alsarraj

Neurosurgery Department, King Abdulaziz Medical City, 21423, Jeddah, Saudi Arabia

Sarah Alqarni

You can also search for this author in PubMed   Google Scholar

Contributions

AA: Acquisition of Data, Analysis and Interpretation of Data, Drafting the Article, Critically Revising the Article, Drafting the Article, Reviewed submitted version of manuscript, Approved the final version of the manuscript on behalf of all authors. Study supervision; MA: Conception and Design, Analysis and Interpretation of Data, Reviewed submitted version of manuscript, Analysis and Interpretation of Data; SA: Acquisition of Data, Conception and Design, Critically Revising the Article, Analysis and Interpretation of Data, Administrative / technical / material support.

Corresponding author

Correspondence to Abdulraheem Alomari .

Ethics declarations

Ethics approval and consent to participate.

Not applicable.

Consent for publication

Competing interests.

The authors declare no competing interests.

Additional information

Publisher’s note.

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Rights and permissions

Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/ . The Creative Commons Public Domain Dedication waiver ( http://creativecommons.org/publicdomain/zero/1.0/ ) applies to the data made available in this article, unless otherwise stated in a credit line to the data.

Reprints and permissions

About this article

Cite this article.

Alomari, A., Alsarraj, M. & Alqarni, S. The learning curve in endoscopic transsphenoidal skull-base surgery: a systematic review. BMC Surg 24 , 135 (2024). https://doi.org/10.1186/s12893-024-02418-y

Download citation

Received : 21 September 2023

Accepted : 20 April 2024

Published : 05 May 2024

DOI : https://doi.org/10.1186/s12893-024-02418-y

Share this article

Anyone you share the following link with will be able to read this content:

Sorry, a shareable link is not currently available for this article.

Provided by the Springer Nature SharedIt content-sharing initiative

• Endoscopic skull base
• Transsphenoidal surgery

BMC Surgery

ISSN: 1471-2482

• Submission enquiries: [email protected]
• General enquiries: [email protected]

Log in using your username and password

• Search More Search for this keyword Advanced search
• Latest Content
• BMJ Journals More You are viewing from: Google Indexer

You are here

• Volume 10, Issue 1
• Incidence and prevalence of interstitial lung diseases worldwide: a systematic literature review
• Article Text
• Article info
• Citation Tools
• Rapid Responses
• Article metrics

• http://orcid.org/0000-0001-9784-416X Rikisha Shah Gupta 1 , 2 ,
• Ardita Koteci 3 , 4 ,
• Ann Morgan 3 , 4 ,
• Peter M George 5 and
• Jennifer K Quint 1 , 3
• 1 National Heart and Lung Institute , Imperial College London , London , UK
• 2 Real-World Evidence , Gilead Sciences , Foster City , CA , USA
• 3 Imperial College London , London , UK
• 4 NIHR Imperial Biomedical Research Centre , London , UK
• 5 Royal Brompton and Harefield NHS Foundation Trust , London , UK
• Correspondence to Rikisha Shah Gupta; r.shah20{at}imperial.ac.uk

Interstitial lung disease (ILD) is a collective term representing a diverse group of pulmonary fibrotic and inflammatory conditions. Due to the diversity of ILD conditions, paucity of guidance and updates to diagnostic criteria over time, it has been challenging to precisely determine ILD incidence and prevalence. This systematic review provides a synthesis of published data at a global level and highlights gaps in the current knowledge base. Medline and Embase databases were searched systematically for studies reporting incidence and prevalence of various ILDs. Randomised controlled trials, case reports and conference abstracts were excluded. 80 studies were included, the most described subgroup was autoimmune-related ILD, and the most studied conditions were rheumatoid arthritis (RA)-associated ILD, systemic sclerosis associated (SSc) ILD and idiopathic pulmonary fibrosis (IPF). The prevalence of IPF was mostly established using healthcare datasets, whereas the prevalence of autoimmune ILD tended to be reported in smaller autoimmune cohorts. The prevalence of IPF ranged from 7 to 1650 per 100 000 persons. Prevalence of SSc ILD and RA ILD ranged from 26.1% to 88.1% and 0.6% to 63.7%, respectively. Significant heterogeneity was observed in the reported incidence of various ILD subtypes. This review demonstrates the challenges in establishing trends over time across regions and highlights a need to standardise ILD diagnostic criteria.PROSPERO registration number: CRD42020203035.

• Asbestos Induced Lung Disease
• Clinical Epidemiology
• Interstitial Fibrosis
• Systemic disease and lungs

This is an open access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited, appropriate credit is given, any changes made indicated, and the use is non-commercial. See:  http://creativecommons.org/licenses/by-nc/4.0/ .

https://doi.org/10.1136/bmjresp-2022-001291

Statistics from Altmetric.com

Request permissions.

If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.

Introduction

Interstitial lung disease (ILD) is a collective term representing a diverse group of lung conditions characterised by the presence of non-infective infiltrates, most commonly in the pulmonary interstitium and alveoli, which in certain cases manifest as architectural distortion and irreversible fibrosis. These conditions vary in their aetiology, clinical pathways, severity and prognosis. 1 Some conditions resolve completely without pharmacological intervention, whereas others, such as idiopathic pulmonary fibrosis (IPF) and non-IPF progressive fibrosing (PF) ILDs, inexorably progress to respiratory failure and premature mortality despite treatment.

Given its universally progressive nature and poor prognosis, IPF has attracted the most research attention and the current literature suggests a wide variation in disease distribution across Europe and USA. IPF prevalence varies between 0.63 and 7.6 per 100 000 persons in the USA and Europe 2 3 with a sharp increase with age.

More recently, there have been several studies investigating the incidence and prevalence of non-IPF ILDs, mainly autoimmune ILDs. Most of these reviews included studies drawn from single centres. Epidemiological data for non-IPF ILDs is inconsistent which makes it challenging to fully appreciate the ILD landscape. A recent review reported the prevalence of ILD in myositis conditions ranged from 23% in America to 50% in Asia. 4 Sambataro et al 5 reported about 20% of primary Sjogren’s syndrome patients were diagnosed with ILD. Additionally, there have been a few studies evaluating the incidence of drug induced ILD (DILD). 6–8 Guo et al 9 reported ILD incidence ranged from 4.6 to 31.5 per 100 000 persons in Europe and North America. A recent study using Global Burden of Disease data indicated the global ILD incidence in the past 10 years has risen by 51% (313.2 cases in 1990 to 207.2 per 1 00 000 cases in 2019). 10 These published estimates highlight a discernible variation in the ILD epidemiology across countries. It is unclear whether this is an ‘actual’ difference in the numbers across regions or whether the heterogeneity is driven by lack of guidelines and inconsistencies in ILD diagnostic pathways and standards of care. Likewise, while evidence suggests that the incidence of ILD has been rising over time, 9 whether this increase reflects a true increase in the disease burden, possibly related to an ageing population or whether this is due to improvements in detection, increased availability of cross-sectional imaging or coding practices over time is unknown.

This systematic review appraises the published literature on the incidence and prevalence of various ILDs over the last 6 years. We aimed to provide a comprehensive understanding of global incidence and prevalence. Specifically, we sought to identify areas where data are robust, to better appreciate the burden of ILD conditions and to comprehend the implications on healthcare utilisation and resources. We also set out to highlight areas where there remains a need for further study.

Study registration

This protocol has been drafted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocols guidelines 11 and registered with the International Prospective Register of Systematic Reviews, PROSPERO ( CRD42020203035 ). Please refer to the online supplemental material for the full study protocol.

Supplemental material

Search strategy and selection criteria.

A systematic search of Medline and Embase was carried out in September 2021 to identify relevant studies investigating the incidence and prevalence of various ILDs. The search criteria were developed with support of librarian ( online supplemental figure E1 ). Due to the high volume of papers, we restricted this study period to papers published in the past 6 years. This search was limited to human studies written in English that were published between 2015 and 2021. The full search strategy and data sources included are described in online supplemental material .

Study population

Inclusion criteria included observational studies reporting the incidence and/or prevalence of individual ILDs, with study participants aged over 18 years old. Randomised controlled trials, case reports, reviews and conference abstracts were excluded. Studies which referred to DILD only were excluded because (1) there were many abstracts reporting on DILD, therefore this could be a standalone review and (2) epidemiology of DILD was a subject of a recent systematic review. 12 The first author (RG) screened all records by title and abstract; to begin with, the second reviewer (AK) independently screened 10% of all records. If there was a disagreement between RG and AK, an additional 15% were screened by AK. All studies identified as eligible for full text review were reviewed by RG, with AK reviewing 50% of eligible studies. Any disagreement was resolved through discussion with other authors, including an ILD expert. Reference of included studies were searched for additional literature.

Following full text review, RG carried out data extraction for eligible studies. AK independently extracted data for 25% of studies using the same template. RG assessed the quality for all included studies, reporting incidence and/or prevalence using a modified Newcastle Ottawa Scale (NOS). There were two NOS modified scales, one each for studies reporting prevalence and/incidence. AK independently assessed the quality of 25% of included studies. If there was a discrepancy between the data extraction and/or quality assessment conducted by RG and AK, then additional 15% were extracted and/or reviewed by AK.

It was noted that for IPF, many authors adopted what they termed ‘broad’ and ‘narrow’ case definitions. For example, Raghu et al 2 defined patients with International Classification of Disease, Ninth Revision (ICD-9) code 516.3 as a broadly defined case of IPF, and those who had this ICD-9 code alongside a claim for a surgical lung biopsy, transbronchial lung biopsy, or CT thorax as a narrowly defined case. We summarised the data using various reported case definitions. If multiple estimates were reported in a study, only the most recent estimate was included in this review.

There were two common themes around the reporting of prevalence. Studies drawn from the general population (reported prevalence per 100 000 persons) and studies drawn from multicentre or single centres (reported prevalence as the proportion of patients with ILD in the study cohort).

For this review, we have classified ILDs based on aetiology, grouped by conditions linked to environmental or occupational exposures, conditions typified by granulomatous inflammation, autoimmune ILDs and ILDs with no known cause ( online supplemental figure E2 ). 1

Evidence synthesis

The initial plan for this review was to conduct meta-analysis. However, due to high heterogeneity, we were unable to meta-analyse. Therefore, we have proceeded with data synthesis across the ILD subgroups.

Total number of included studies

The literature search yielded a total of 12 924 studies, of which 80 were included in this review. Online supplemental figure E3 demonstrates the selection process for all studies and highlights reasons for exclusion at each stage.

Although 80 unique publications were included, some papers explored the epidemiology of more than one ILD, the total count of reported estimates is 88. Half of the included publications explored autoimmune-related ILDs (n=44/88)( online supplemental figure E4 ).

Geographically, ILD publications represented all major world regions, but were predominantly from Asia (n=30, 34.1%) and Europe (n=23, 26.1%) ( figure 1 ).

• Download figure
• Open in new tab
• Download powerpoint

Geographical distribution of publications included.

Studies reporting prevalence

Eight studies reported the prevalence of IPF in general population. Prevalence of IPF was commonly reported applying ‘primary’, ‘broad’, ‘intermediate’ and/or ‘narrow’ case definitions. In the general population, the prevalence of IPF ranged from 7 to 1650 per 100 000 persons ( table 1 ). When explored within various case definitions, the prevalence for ‘broad’ cases ranged from 11 (USA, 2010) 2 to 1160 (USA, 2021) 16 ; for ‘narrow’ cases, this ranged from 7 (USA, 2010) 2 to 725 (USA, 2019). 16 There was only one study that reported IPF prevalence of 8.6% using a multicentre study setting. 19

• View inline

Studies reporting IPF prevalence per 100 000 persons by various case definitions

Twelve studies reported estimates for non-IPF ILDs in the general population ( online supplemental figure E5 ), with most of these conducted in the USA. The prevalence of systemic sclerosis (SSc) ILD in the general population ranged from 2.3 (Canada, 2018) 20 to 19 (USA, 2017) 21 per 100 000 persons. The highest SSc-ILD prevalence was reported in Medicare data which included patients aged 65 years and above. 21 22 For rheumatoid arthritis (RA) ILD, prevalence in an RA Medicare cohort was 2%. 23

Forty-six studies reported the prevalence of autoimmune-related ILD in cohorts of patients with an autoimmune condition or occupational ILD in workers with specific exposures. These studies primarily reported prevalence as a proportion, with the denominator representing patients with an autoimmune disorder or people working at a factory with exposure to certain agents, such as silica or asbestosis ( figure 2 ). Most of these estimates were drawn from cohorts at single or multiple tertiary centres, disease registries or a factory in the case of occupational ILD. Significant heterogeneity was noted in the reported prevalence of ILD associated with SSc, RA and Sjogren’s ( figure 2 ). The prevalence of ILD in SSc ranged from 26.1% (Australia, 2015) 36 to 88.1% (India, 2013). 44 Similarly, Sjogren’s ILD ranged from 1% (Sweden, 2011) 55 to 87.8% (Saudi Arabia, 2021). 56 In addition to dissimilarities in the prevalence across various regions, we also observed variation within region-specific estimates. For example, the 4 studies 47 50–52 which reported Sjogren’s ILD prevalence within China, estimated a 4-fold variation in magnitude (18.6% in 2011 47 to 78.6% in 2014). 52 Likewise, for RA ILD, there was substantial variation in the reported prevalence in Egypt (0.8% vs 63.7%). 31 32 Among the occupational-related ILDs ( figure 2 ), silicosis was the most explored condition (n=8)). Among these eight studies, there was a considerable variation in the reported prevalence of silicosis. Souza et al 61 reported an approximately 7-fold higher estimate of silicosis prevalence than that reported by Siribaddana et al (37% vs 5.6%, respectively). 65

Studies reporting non-IPF prevalence as percentage of study population. DM, dermatomyositis; HP, hypersensitivity pneumonitis; IIP, idiopathic interstitial pneumonia; ILD, interstitial lung disease; LAM, lymphangioleiomyomatosis; MCTD, mixed connective tissue disorder; multiC, multicentre; PLCH, pulmonary langerhans cell histiocytosis; PM, polymyositis; RA, rheumatoid arthritis; reg, registry; single, single centre; SSc, systemic sclerosis. Details on the study population, sample size and ILD diagnosis methods are summarised in online supplemental tables E1–E31 .

Studies reporting incidence

Significant discrepancies were observed in reported ILD incidence across subgroups and individual conditions, mainly due to differences in the study setting. Depending on the study setting and type of data source used, some authors reported an incidence rate (per 100 000 person-years), while others reported incidence proportion. Table 2 lists IPF incidence by case classification and country, and figure 3 provides a list of studies reporting incidence of non-IPF ILDs.

Published estimates of IPF incidence, stratified by various case definitions

Studies reporting ILD incidence, grouped by ILD subgroups. ICD-9-CM, International Classification of Disease, Ninth Revision, Clinical Modification; ILD, interstitial lung disease; py, person-years; RA, rheumatoid arthritis; SSc, systemic sclerosis. Ɨ Narrow silicosis definition used: Medicare beneficiaries with any claim that included ICD-9-CM code 502, pneumoconiosis due to other silica or silicates, listed in any position during 1999–2014, with at least one inpatient, skilled nursing or home health agency claim, or at least two outpatient provider claims within 365 days of each other and cases with a chest X-ray or CT scan 30 days before or 30 days after a silicosis claim. Details on the study population, sample size and ILD diagnosis methods are summarised in online supplemental tables E1–E31 .

In this review, we synthesised the evidence for the incidence and prevalence of ILDs from studies published between 2015 and 2021. Considering the changing ILD nomenclature and the desire to reflect more current estimates, in this review, we decided to restrict the study period to past 6 years. We took this conscious effort with the aim to limit the heterogeneity across reported estimates. We evaluated 39 incidence and 78 prevalence estimates for individual ILD disorders that were distributed globally. We noted an increase in the number of studies investigating non-IPF ILDs and more specifically autoimmune ILDs in recent years. There was a 6-fold rise in the autoimmune ILDs studies, in 2021 when compared with 2015 (18 vs 3 studies, respectively). This increase in non-IPF ILD studies may be related to the emergence of antifibrotic therapies for non-IPF fibrosing lung diseases. 91–93 Interestingly, the publication trend for IPF has remained unchanged.

This review revealed considerable inconsistencies in the incidence and prevalence estimated of the main ILD subgroups. The reported prevalence of IPF ranged from 7 to 1650 per 100 000 persons, 2 16 an approximately 800-fold difference across case definitions, despite most studies reporting IPF prevalence in the general population. The incidence and prevalence estimates reported by Zhang et al 16 were a notable outlier; this study was based on the USA veterans’ healthcare database which included mostly White patients aged over 70 years—the demographic in which IPF is most common. Aside from this study, the majority of studies reported a prevalence of IPF ranging from 7 to 42 per 100 000 persons across different case definitions. 2 17

Unlike prevalence, we found considerable inconsistencies in how the incidence of IPF is reported. An important factor is the lack of uniformity in reporting units. Half of the studies reported incidence using person-years, whereas others reported per 100 000 person-years. We were, therefore, unable to compare incidence estimates in a similar fashion to prevalence. It is also important to note that changes in diagnostic guidelines for IPF over the years may have made it more challenging to accurately estimate its burden and temporal trends. 94–96

For non-IPF subgroups, such as autoimmune ILDs, there were wide variations in prevalence estimates between countries and within different healthcare settings in the same country. Overall, the variation in prevalence and incidence estimates was even greater for non-IPF ILDs than IPF. This can be attributed to several factors. First, in clinical practice, it is common for the clinical presentation and serological autoantibody profiles to result in overlap syndromes. Autoimmune conditions can coexist and patients with occupational ILDs may also have autoimmune conditions. Such fluidity of diagnoses at a clinical level reflects the challenges in estimating non-IPF ILDs. Second, the denominator more frequently differs for non-IPF ILDs, resulting in lack of standardised reporting. Unlike IPF, for which there are published validated algorithms to identify ‘true’ cases in the general population. 18 24 97 For non-IPF ILDs, studies relied on disease registries or were conducted at single/multispecialist clinics.

Majority of the autoimmune-related ILD estimates were in RA and SSc ILD. When assessing SSc ILD prevalence, we observed a wide range (26.1% to 88.1%) 37 44 in reported estimates, but when studies were dichotomised into single-centre studies and multicentre studies, it became clear that the highest variability was contributed by single centre studies (SSc prevalence, 31.2%–88.1%). 43–46 Owing to a smaller number of studies reporting incidence, we were unable to observe whether the same challenge existed.

The prevalence of silicosis ranged from 5.6% 65 to 37% 61 in workers exposed to silica. Occupational ILD studies were conducted at a factory, in a neighbourhood with proximity to industries, a registry or multicentre settings. Therefore, lack of generalisability and applicability of findings only to certain populations contributed largely to the wide variabilities of these reported estimates. The geographical distribution of occupational ILD papers alludes to dominance of exposure related ILDs in low-income and middle-income countries in Asia and South America (42.8% were in Asia).

While historical diagnostic classification has been founded on underlying aetiology or clinical pathways, there is now a growing emphasis on disease behaviour. 98 99 Attention has focused on a subgroup of ILD patients who go on to develop a PF phenotype. IPF is the archetypal PF ILD but other ILDs such as chronic hypersensitivity pneumonitis (HP), SSc ILD can exhibit ‘IPF-like’ behaviour, including rapid decline in lung function and early mortality. 100 The epidemiology of PF ILD is particularly challenging to examine as accepted guidelines on definition and diagnosis have yet to be published The reported prevalence of PF ILDs (per 100 000 persons) was 19.4 in France and 57.8 in the USA. 88 89 The future direction of research will likely focus on PF ILD as a phenotype which transcends previously adhered-to diagnostic labels and is associated with poorer outcomes and increased mortality. 100 101

Among the 39 studies reporting ILD incidence ( online supplemental figure E6 ), most studies were categorised as medium risk (n=25/39, 64.1%). Two studies were categorised as high-risk primarily because of lack of information on ILD diagnosis and poor quality of reporting estimates (ie, descriptive statistics were not reported, were incomplete or did not include proper measures of dispersion).

Similarly, there were 78 prevalence assessments ( online supplemental figure E7 ) of which approximately 18% (n=14/78) were categorised as high risk, 64.1% (n=50/78) as medium risk and 18% (n=14/76) as low risk. Most studies assessed as high risk were studies reporting autoimmune ILDs, mainly because of ILD diagnosis, single-centre studies or small sample size. Most of the studies reporting prevalence based on large healthcare datasets or disease registries were classified as low risk.

There are several strengths of this systematic review. We have provided an assessment of the incidence and prevalence of several ILD conditions globally and have grouped ILDs based on their aetiology to allow the appraisal of incidence and/prevalence at a disease level with as much granularity as possible. This review underlines the need for standardisation of diagnostic classifications for non-IPF ILDs—the narrower estimates for IPF provide the evidence that clear and consistent diagnostic guidelines are of great clinical utility. Guidelines have recently emerged for the diagnosis of HP 102 103 which we envisage will further improve the epidemiological reporting of this important condition, although incorporation of guidelines into routine clinical practice and then into epidemiological estimates takes time. Cross-specialty guideline groups will undoubtedly improve standardisation of reporting for autoimmune driven ILDs.

It is possible that genetic differences between individuals from different ethnic backgrounds may play a role in the global variability in incidence and prevalence. For example, the MUC5B promoter polymorphism (rs35705950) is the dominant risk factor for IPF 104 and is also a key risk factor for other ILDs such as RA. 105 This gain of function polymorphism is frequent in those of European decent but almost completely absent in those of African ancestry. 106 As more research is performed unravelling the complex interplay between genetics and environment in the development of ILD, it is likely that genetic variability will be found to play an important role in the global variability of ILD.

Despite the strengths, there are limitations to this systematic review. The certainty of the ILD case definition varied across studies. It was not always possible to be sure of how reliable the ascertainment method was. However, we attempted to reflect the differences in the ILD diagnostic methods in our risk of bias quality assessment. Along with the uncertainty in the diagnosis of ILD, there were different disease definitions used across studies. Therefore, in this review due to high heterogeneity, in how ILD was defined, we were unable to perform a meta-analysis. In this review, we have only included studies reporting ILD estimates in general populations, registries or populations with a specific disorder of interest. For single-centre studies reporting incidence and/or prevalence of autoimmune or exposure ILDs, the estimates were not generalisable and this has been reflected in the risk of bias quality assessment score. This review is limited to English publications only. However, due to high volume of papers found with the study period, we are confident it has a minimal effect on the overall conclusion. 107

This review highlights the lack of uniformity in the published estimates of incidence and prevalence of ILD conditions. In addition, there is a dissimilarity in disease definitions across the studies and geographical regions. Owing to these discrepancies, we were unable to derive estimates for the global incidence and prevalence of ILD and moreover unable to confirm whether there has been a ‘true’ increase in ILD incidence over time. Revisions to diagnostic criteria have augmented the challenges of estimating incidence and prevalence of individual ILD conditions and determining the drivers for temporal trends in incidence. Improving our estimates of the burden of fibrosing lung conditions is essential for future health service planning, a need that has been heightened by the development of new antifibrotic treatments. Guidelines have recently emerged for non-IPF ILDs, we envisage this may improve the epidemiological reporting for future research. There is a fundamental need to standardise ILD diagnosis, disease definitions and reporting in order to provide the data which will drive the provision of a consistently high level of care for these patients across the globe. 108

Ethics statements

Patient consent for publication.

Not applicable.

• ↵ American Thoracic Society/European Respiratory Society international multidisciplinary consensus classification of the idiopathic interstitial pneumonias. This joint statement of the American Thoracic Society (ATS), and the European Respiratory Society (ERS) was adopted by the ATS board of directors, June 2001 and by the ERS Executive Committee, June 2001 . Am J Respir Crit Care Med 2002 ; 165 : 277 – 304 . doi:10.1164/ajrccm.165.2.ats01 OpenUrl CrossRef PubMed
• Hou Q , et al
• Wang Y-X , et al
• Sambataro D ,
• Sambataro G ,
• Pignataro F , et al
• Roubille C ,
• Micheletto L , et al
• Salliot C ,
• van der Heijde D
• Xia S , et al
• Global Burden of Disease Collaborative Network
• McKenzie JE ,
• Bossuyt PM , et al
• Weatherley N ,
• Swift AJ , et al
• Madotto F ,
• Caminati A , et al
• Raimundo K ,
• Broder MS , et al
• Myong J-P ,
• Kim H-R , et al
• Lee JS , et al
• Hopkins RB ,
• Fell C , et al
• Strongman H ,
• Kaunisto J ,
• Kelloniemi K ,
• Sutinen E , et al
• Quansah K ,
• Hassan S , et al
• Wallace L ,
• Patnaik P , et al
• Solomon JJ ,
• Olson AL , et al
• Sparks JA ,
• Cho S-K , et al
• Kang EH , et al
• Choi C-B , et al
• Kronzer VL ,
• Westerlind H ,
• Alfredsson L , et al
• Nikiphorou E , et al
• Benavidez F , et al
• Wu N , et al
• Xu D , et al
• Elfishawi MM ,
• ElArousy MH , et al
• Md Yusof MY ,
• Darby M , et al
• Duarte AC ,
• Porter JC ,
• McFarlane IM ,
• Bhamra MS , et al
• Morrisroe K ,
• Huq M , et al
• Fairley JL ,
• Proudman S , et al
• Noviani M ,
• Saffari SE ,
• Tan JL , et al
• Vandecasteele E ,
• Melsens K ,
• Vanhaecke A , et al
• Simeón-Aznar CP ,
• Fonollosa-Plá V ,
• Tolosa-Vilella C , et al
• Sánchez-Cano D ,
• Ortego-Centeno N ,
• Callejas JL , et al
• Lescoat A ,
• Huang S , et al
• Tanguy M , et al
• Janardana R ,
• Surin AK , et al
• Tomiyama F ,
• Watanabe R ,
• Ishii T , et al
• Wangkaew S ,
• Euathrongchit J ,
• Wattanawittawas P , et al
• Wang L , et al
• Dominique S ,
• Schmidt J , et al
• Leong R-L , et al
• Zhang X-W ,
• He J , et al
• Zhang X-Y , et al
• Qiu M , et al
• Kampolis CF ,
• Fragkioudaki S ,
• Mavragani CP , et al
• Manfredi A ,
• Sebastiani M ,
• Cerri S , et al
• AlQahtani BS ,
• AlHamad EH , et al
• Kvarnström M ,
• Ottosson V ,
• Nordmark B , et al
• Nilsson AM ,
• Aaltonen HL ,
• Olsson P , et al
• Poinen-Rughooputh S ,
• Rughooputh MS ,
• Guo Y , et al
• Requena-Mullor M ,
• Alarcón-Rodríguez R ,
• Parrón-Carreño T , et al
• van Tongeren M ,
• Gusso AM , et al
• Ehrlich R ,
• Fielding K , et al
• Dimitriadis C , et al
• Silanun K ,
• Chaiear N ,
• Rechaipichitkul W
• Siribaddana AD ,
• Wickramasekera K ,
• Palipana WM , et al
• Kim Y , et al
• Wickramatillake BA ,
• Fernando MA ,
• Braillard Poccard A , et al
• Ishizuka M ,
• Huang H-L ,
• Lin P-Y , et al
• Olaosebikan H ,
• Adeyeye O ,
• Akintayo R , et al
• Duchemann B ,
• Annesi-Maesano I ,
• Jacobe de Naurois C , et al
• Reiseter S ,
• Gunnarsson R ,
• Mogens Aaløkken T , et al
• Üzmezoğlu BA , et al
• Coquart N ,
• Cadelis G ,
• Tressières B , et al
• Kim D , et al
• Belbasis L ,
• Evangelou E
• Kim Y-K , et al
• Gjonbrataj J ,
• Bahn YE , et al
• Han B , et al
• DeBono NL ,
• Logar-Henderson C , et al
• Szeszenia-Dąbrowska N ,
• Świątkowska B ,
• Sobala W , et al
• Thomsen RW ,
• Flachs EM , et al
• Murofushi KN ,
• Gosho M , et al
• Tamaki T , et al
• Fernández Pérez ER ,
• Raimundo K , et al
• Yoo SH , et al
• Larrieu S ,
• Boussel L , et al
• Patnaik P ,
• Hartmann N , et al
• Flaherty KR ,
• Brown KK , et al
• Highland KB ,
• Distler O ,
• Kuwana M , et al
• Kreuter M , et al
• Collard HR ,
• Egan JJ , et al
• Rochwerg B ,
• Zhang Y , et al
• Remy-Jardin M ,
• Myers JL , et al
• Urbania T ,
• Husson G , et al
• Ryerson CJ ,
• Travis WD ,
• Costabel U ,
• Hansell DM , et al
• George PM ,
• Spagnolo P ,
• Martinez FJ ,
• Walsh SLF , et al
• Lynch DA , et al
• Seibold MA ,
• Speer MC , et al
• Ebstein E , et al
• Genomes Project C ,
• Brooks LD , et al
• Nussbaumer-Streit B ,
• Klerings I ,
• Dobrescu AI , et al
• Richeldi L , et al

Supplementary materials

Supplementary data.

This web only file has been produced by the BMJ Publishing Group from an electronic file supplied by the author(s) and has not been edited for content.

• Data supplement 1

Twitter @DrPeter_George

Contributors RG, AM, PMG and JKQ developed the research question. RG, AM, PMG and JKQ developed the study protocol. RG developed the search strategy with input from AM and JKQ. RG screened the studies for inclusion, extracted the data from included studies and carried out quality assessment of the data. AK was the secondary reviewer for screening, data extraction and quality assessment. PMG supported with the understanding of various ILD diseases and their clinical pathways. All authors interpreted the review results. RG drafted the manuscript. All authors read, commented on and approved the manuscript.

Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

Map disclaimer The inclusion of any map (including the depiction of any boundaries therein), or of any geographic or locational reference, does not imply the expression of any opinion whatsoever on the part of BMJ concerning the legal status of any country, territory, jurisdiction or area or of its authorities. Any such expression remains solely that of the relevant source and is not endorsed by BMJ. Maps are provided without any warranty of any kind, either express or implied.

Competing interests RG is a current employee of Gilead Sciences, outside the submitted work. JKQ has received grants from The Health Foundation, MRC, GSK, Bayer, BI, British Lung Foundation, IQVIA, Chiesi AZ, Insmed and Asthma UK. JKQ has received personal fees for advisory board participation or speaking fees from GlaxoSmithKline, Boehringer Ingelheim, AstraZeneca, Bayer and Insmed. PMG has received grants from the MRC, Boehringer Ingelheim and Roche Pharmaceuticals and personal fees from Boehringer Ingelheim, Roche Pharmaceuticals, Teva, Cippla, AZ and Brainomix. AK and AM have nothing to disclose.

Provenance and peer review Not commissioned; externally peer reviewed.

Supplemental material This content has been supplied by the author(s). It has not been vetted by BMJ Publishing Group Limited (BMJ) and may not have been peer-reviewed. Any opinions or recommendations discussed are solely those of the author(s) and are not endorsed by BMJ. BMJ disclaims all liability and responsibility arising from any reliance placed on the content. Where the content includes any translated material, BMJ does not warrant the accuracy and reliability of the translations (including but not limited to local regulations, clinical guidelines, terminology, drug names and drug dosages), and is not responsible for any error and/or omissions arising from translation and adaptation or otherwise.

Read the full text or download the PDF:

• Schedule an Appointment

• Undergraduate Students in AS&E and SMFA
• Graduate Students in AS&E and SMFA
• Faculty & Staff
• Parents and Families
• What is a Career Community?
• Reflect, Discover & Explore Multiple Interests
• Arts, Communications & Media
• Education, Nonprofit & Social Impact
• Engineering, Technology & Physical Sciences
• Finance, Consulting, Entrepreneurship & Business
• Government, International Affairs & Law
• Healthcare, Life Sciences & the Environment
• Exploring Your Interests, Careers & Majors
• Writing Resumes & Cover Letters
• Finding an Internship
• Finding Jobs & Fellowships
• Preparing for Interviews
• Applying to Graduate & Professional School
• First Generation
• International Students
• Black, Indigenous & People of Color
• Students with Disabilities
• Students with Undocumented Status
• Women & Gender
• For Employers
• Contact & Location
• Career Fellows
• Career Services by School

Case Interview: Complete Prep Guide

• Share This: Share Case Interview: Complete Prep Guide on Facebook Share Case Interview: Complete Prep Guide on LinkedIn Share Case Interview: Complete Prep Guide on X

Welcome to our preparation tips for case interviews!  Whether you are just curious about case interviews or are planning to apply for consulting internships or full-time jobs, these tips and resources will help you feel more prepared and confident.

A case interview is a role playing exercise in which an employer assesses how logically and persuasively you can present a case. Rather than seeing if you get the “correct” answer, the objective is to evaluate your thought process. ( Adapted with permission from Case In Point: Complete Case Interview Preparation by Marc Cosentino). 

Case interviews are very commonly used in the interview process for consulting firms and companies in similar industries. In the case interview, you will typically be given a business problem and then asked to solve it in a structured way. Learning this structure takes preparation and practice. You can learn more and practice using the resources listed below.  

Why are Case Interviews Used?

Case interviews allow employers to test and evaluate the following skills:

• Analytical skills and logical ability to solve problems
• Structure and thought process
• Ability to ask for relevant data/information
• Tolerance for ambiguity and data overload
• Poise and communication skills under pressure and in front of a client

How can I prepare for Case Interviews?

1.) Read Management Consulted’s “Case Interview: Complete Prep Guide (2024)”

Management Consulted is a FREE resource for Tufts students : case and consulting resources such as 500 sample cases, Case Interview Bootcamp,  Market Sizing Drills, Math Drills, case videos, consulting firm directory, and more

2.) Review additional resources:

• Case in Point – This book, by Marc Cosentino, is a comprehensive guide that walks you through the case interview process from beginning to end. This guide has helped many students over the years and can serve as an excellent foundation for how to approach business problems
• Casequestions.com – The companion website to Marc Cosentino’s book listed above offers preparation for case interviews, along with links to top 50 consulting firms
• Management Consulting Case Interviews: Cracking The Case – tips for case interviews from the other side of the table, from Argopoint, a Boston management consulting firm specializing in legal department consulting for Fortune 500 companies
• Preplounge.com – Free case preparation access for to up to 6 practice interviews with peers, selected cases, and video case solutions
• RocketBlocks – Features consulting preparation such as drills and coaching
• Practice sample online cases on consulting firm websites such as McKinsey , BCG , Bain , Deloitte and more!  

3.) Schedule a mock case interview appointment with  Karen Dankers or Kathy Spillane , our advisors for the Finance, Consulting, Entrepreneurship, and Business Career Community.

4.) PRACTICE PRACTICE PRACTICE cases out loud on your own (yes, that can feel odd) or preferably, with another person. See #2 and #3 above for resources and ideas to find partners to practice live cases

5.) Enjoy and have fun solving business problems!