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Ten Simple Rules for Writing a Literature Review

Marco pautasso.

1 Centre for Functional and Evolutionary Ecology (CEFE), CNRS, Montpellier, France

2 Centre for Biodiversity Synthesis and Analysis (CESAB), FRB, Aix-en-Provence, France

Literature reviews are in great demand in most scientific fields. Their need stems from the ever-increasing output of scientific publications [1] . For example, compared to 1991, in 2008 three, eight, and forty times more papers were indexed in Web of Science on malaria, obesity, and biodiversity, respectively [2] . Given such mountains of papers, scientists cannot be expected to examine in detail every single new paper relevant to their interests [3] . Thus, it is both advantageous and necessary to rely on regular summaries of the recent literature. Although recognition for scientists mainly comes from primary research, timely literature reviews can lead to new synthetic insights and are often widely read [4] . For such summaries to be useful, however, they need to be compiled in a professional way [5] .

When starting from scratch, reviewing the literature can require a titanic amount of work. That is why researchers who have spent their career working on a certain research issue are in a perfect position to review that literature. Some graduate schools are now offering courses in reviewing the literature, given that most research students start their project by producing an overview of what has already been done on their research issue [6] . However, it is likely that most scientists have not thought in detail about how to approach and carry out a literature review.

Reviewing the literature requires the ability to juggle multiple tasks, from finding and evaluating relevant material to synthesising information from various sources, from critical thinking to paraphrasing, evaluating, and citation skills [7] . In this contribution, I share ten simple rules I learned working on about 25 literature reviews as a PhD and postdoctoral student. Ideas and insights also come from discussions with coauthors and colleagues, as well as feedback from reviewers and editors.

Rule 1: Define a Topic and Audience

How to choose which topic to review? There are so many issues in contemporary science that you could spend a lifetime of attending conferences and reading the literature just pondering what to review. On the one hand, if you take several years to choose, several other people may have had the same idea in the meantime. On the other hand, only a well-considered topic is likely to lead to a brilliant literature review [8] . The topic must at least be:

• interesting to you (ideally, you should have come across a series of recent papers related to your line of work that call for a critical summary),
• an important aspect of the field (so that many readers will be interested in the review and there will be enough material to write it), and
• a well-defined issue (otherwise you could potentially include thousands of publications, which would make the review unhelpful).

Ideas for potential reviews may come from papers providing lists of key research questions to be answered [9] , but also from serendipitous moments during desultory reading and discussions. In addition to choosing your topic, you should also select a target audience. In many cases, the topic (e.g., web services in computational biology) will automatically define an audience (e.g., computational biologists), but that same topic may also be of interest to neighbouring fields (e.g., computer science, biology, etc.).

Rule 2: Search and Re-search the Literature

After having chosen your topic and audience, start by checking the literature and downloading relevant papers. Five pieces of advice here:

• keep track of the search items you use (so that your search can be replicated [10] ),
• keep a list of papers whose pdfs you cannot access immediately (so as to retrieve them later with alternative strategies),
• use a paper management system (e.g., Mendeley, Papers, Qiqqa, Sente),
• define early in the process some criteria for exclusion of irrelevant papers (these criteria can then be described in the review to help define its scope), and
• do not just look for research papers in the area you wish to review, but also seek previous reviews.

The chances are high that someone will already have published a literature review ( Figure 1 ), if not exactly on the issue you are planning to tackle, at least on a related topic. If there are already a few or several reviews of the literature on your issue, my advice is not to give up, but to carry on with your own literature review,

The bottom-right situation (many literature reviews but few research papers) is not just a theoretical situation; it applies, for example, to the study of the impacts of climate change on plant diseases, where there appear to be more literature reviews than research studies [33] .

• discussing in your review the approaches, limitations, and conclusions of past reviews,
• trying to find a new angle that has not been covered adequately in the previous reviews, and
• incorporating new material that has inevitably accumulated since their appearance.

When searching the literature for pertinent papers and reviews, the usual rules apply:

• be thorough,
• use different keywords and database sources (e.g., DBLP, Google Scholar, ISI Proceedings, JSTOR Search, Medline, Scopus, Web of Science), and
• look at who has cited past relevant papers and book chapters.

Rule 3: Take Notes While Reading

If you read the papers first, and only afterwards start writing the review, you will need a very good memory to remember who wrote what, and what your impressions and associations were while reading each single paper. My advice is, while reading, to start writing down interesting pieces of information, insights about how to organize the review, and thoughts on what to write. This way, by the time you have read the literature you selected, you will already have a rough draft of the review.

Of course, this draft will still need much rewriting, restructuring, and rethinking to obtain a text with a coherent argument [11] , but you will have avoided the danger posed by staring at a blank document. Be careful when taking notes to use quotation marks if you are provisionally copying verbatim from the literature. It is advisable then to reformulate such quotes with your own words in the final draft. It is important to be careful in noting the references already at this stage, so as to avoid misattributions. Using referencing software from the very beginning of your endeavour will save you time.

Rule 4: Choose the Type of Review You Wish to Write

After having taken notes while reading the literature, you will have a rough idea of the amount of material available for the review. This is probably a good time to decide whether to go for a mini- or a full review. Some journals are now favouring the publication of rather short reviews focusing on the last few years, with a limit on the number of words and citations. A mini-review is not necessarily a minor review: it may well attract more attention from busy readers, although it will inevitably simplify some issues and leave out some relevant material due to space limitations. A full review will have the advantage of more freedom to cover in detail the complexities of a particular scientific development, but may then be left in the pile of the very important papers “to be read” by readers with little time to spare for major monographs.

There is probably a continuum between mini- and full reviews. The same point applies to the dichotomy of descriptive vs. integrative reviews. While descriptive reviews focus on the methodology, findings, and interpretation of each reviewed study, integrative reviews attempt to find common ideas and concepts from the reviewed material [12] . A similar distinction exists between narrative and systematic reviews: while narrative reviews are qualitative, systematic reviews attempt to test a hypothesis based on the published evidence, which is gathered using a predefined protocol to reduce bias [13] , [14] . When systematic reviews analyse quantitative results in a quantitative way, they become meta-analyses. The choice between different review types will have to be made on a case-by-case basis, depending not just on the nature of the material found and the preferences of the target journal(s), but also on the time available to write the review and the number of coauthors [15] .

Rule 5: Keep the Review Focused, but Make It of Broad Interest

Whether your plan is to write a mini- or a full review, it is good advice to keep it focused 16 , 17 . Including material just for the sake of it can easily lead to reviews that are trying to do too many things at once. The need to keep a review focused can be problematic for interdisciplinary reviews, where the aim is to bridge the gap between fields [18] . If you are writing a review on, for example, how epidemiological approaches are used in modelling the spread of ideas, you may be inclined to include material from both parent fields, epidemiology and the study of cultural diffusion. This may be necessary to some extent, but in this case a focused review would only deal in detail with those studies at the interface between epidemiology and the spread of ideas.

While focus is an important feature of a successful review, this requirement has to be balanced with the need to make the review relevant to a broad audience. This square may be circled by discussing the wider implications of the reviewed topic for other disciplines.

Rule 6: Be Critical and Consistent

Reviewing the literature is not stamp collecting. A good review does not just summarize the literature, but discusses it critically, identifies methodological problems, and points out research gaps [19] . After having read a review of the literature, a reader should have a rough idea of:

• the major achievements in the reviewed field,
• the main areas of debate, and
• the outstanding research questions.

It is challenging to achieve a successful review on all these fronts. A solution can be to involve a set of complementary coauthors: some people are excellent at mapping what has been achieved, some others are very good at identifying dark clouds on the horizon, and some have instead a knack at predicting where solutions are going to come from. If your journal club has exactly this sort of team, then you should definitely write a review of the literature! In addition to critical thinking, a literature review needs consistency, for example in the choice of passive vs. active voice and present vs. past tense.

Rule 7: Find a Logical Structure

Like a well-baked cake, a good review has a number of telling features: it is worth the reader's time, timely, systematic, well written, focused, and critical. It also needs a good structure. With reviews, the usual subdivision of research papers into introduction, methods, results, and discussion does not work or is rarely used. However, a general introduction of the context and, toward the end, a recapitulation of the main points covered and take-home messages make sense also in the case of reviews. For systematic reviews, there is a trend towards including information about how the literature was searched (database, keywords, time limits) [20] .

How can you organize the flow of the main body of the review so that the reader will be drawn into and guided through it? It is generally helpful to draw a conceptual scheme of the review, e.g., with mind-mapping techniques. Such diagrams can help recognize a logical way to order and link the various sections of a review [21] . This is the case not just at the writing stage, but also for readers if the diagram is included in the review as a figure. A careful selection of diagrams and figures relevant to the reviewed topic can be very helpful to structure the text too [22] .

Rule 8: Make Use of Feedback

Reviews of the literature are normally peer-reviewed in the same way as research papers, and rightly so [23] . As a rule, incorporating feedback from reviewers greatly helps improve a review draft. Having read the review with a fresh mind, reviewers may spot inaccuracies, inconsistencies, and ambiguities that had not been noticed by the writers due to rereading the typescript too many times. It is however advisable to reread the draft one more time before submission, as a last-minute correction of typos, leaps, and muddled sentences may enable the reviewers to focus on providing advice on the content rather than the form.

Feedback is vital to writing a good review, and should be sought from a variety of colleagues, so as to obtain a diversity of views on the draft. This may lead in some cases to conflicting views on the merits of the paper, and on how to improve it, but such a situation is better than the absence of feedback. A diversity of feedback perspectives on a literature review can help identify where the consensus view stands in the landscape of the current scientific understanding of an issue [24] .

Rule 9: Include Your Own Relevant Research, but Be Objective

In many cases, reviewers of the literature will have published studies relevant to the review they are writing. This could create a conflict of interest: how can reviewers report objectively on their own work [25] ? Some scientists may be overly enthusiastic about what they have published, and thus risk giving too much importance to their own findings in the review. However, bias could also occur in the other direction: some scientists may be unduly dismissive of their own achievements, so that they will tend to downplay their contribution (if any) to a field when reviewing it.

In general, a review of the literature should neither be a public relations brochure nor an exercise in competitive self-denial. If a reviewer is up to the job of producing a well-organized and methodical review, which flows well and provides a service to the readership, then it should be possible to be objective in reviewing one's own relevant findings. In reviews written by multiple authors, this may be achieved by assigning the review of the results of a coauthor to different coauthors.

Rule 10: Be Up-to-Date, but Do Not Forget Older Studies

Given the progressive acceleration in the publication of scientific papers, today's reviews of the literature need awareness not just of the overall direction and achievements of a field of inquiry, but also of the latest studies, so as not to become out-of-date before they have been published. Ideally, a literature review should not identify as a major research gap an issue that has just been addressed in a series of papers in press (the same applies, of course, to older, overlooked studies (“sleeping beauties” [26] )). This implies that literature reviewers would do well to keep an eye on electronic lists of papers in press, given that it can take months before these appear in scientific databases. Some reviews declare that they have scanned the literature up to a certain point in time, but given that peer review can be a rather lengthy process, a full search for newly appeared literature at the revision stage may be worthwhile. Assessing the contribution of papers that have just appeared is particularly challenging, because there is little perspective with which to gauge their significance and impact on further research and society.

Inevitably, new papers on the reviewed topic (including independently written literature reviews) will appear from all quarters after the review has been published, so that there may soon be the need for an updated review. But this is the nature of science [27] – [32] . I wish everybody good luck with writing a review of the literature.

Acknowledgments

Many thanks to M. Barbosa, K. Dehnen-Schmutz, T. Döring, D. Fontaneto, M. Garbelotto, O. Holdenrieder, M. Jeger, D. Lonsdale, A. MacLeod, P. Mills, M. Moslonka-Lefebvre, G. Stancanelli, P. Weisberg, and X. Xu for insights and discussions, and to P. Bourne, T. Matoni, and D. Smith for helpful comments on a previous draft.

Funding Statement

This work was funded by the French Foundation for Research on Biodiversity (FRB) through its Centre for Synthesis and Analysis of Biodiversity data (CESAB), as part of the NETSEED research project. The funders had no role in the preparation of the manuscript.

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• How to Write a Literature Review | Guide, Examples, & Templates

How to Write a Literature Review | Guide, Examples, & Templates

Published on January 2, 2023 by Shona McCombes . Revised on September 11, 2023.

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 that you can later apply to your paper, thesis, or dissertation topic .

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 summarize sources—it analyzes, synthesizes , and critically evaluates to give a clear picture of the state of knowledge on the subject.

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Table of contents

What is the purpose of 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, free lecture slides, other interesting articles, frequently asked questions, introduction.

• Quick Run-through
• Step 1 & 2

When you write a thesis , dissertation , or research paper , you will likely 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 its scholarly context
• Develop a theoretical framework and methodology for your research
• Position your work in relation to other researchers and theorists
• Show how your research addresses a gap or contributes to a debate
• Evaluate the current state of research and demonstrate your knowledge of the scholarly debates around your topic.

Writing literature reviews is a particularly important skill if you want to apply for graduate school or pursue a career in research. We’ve written a step-by-step guide that you can follow below.

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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 problem and questions .

Make a list of keywords

Start by creating a list of keywords related to your research question. 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 as 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 useful 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 also use boolean operators to help narrow down your search.

Make sure to 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.

You likely won’t be able to read absolutely everything that has been written on your topic, so it will be necessary to evaluate which sources are most relevant to your research question.

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?
• 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 use our template to summarize and evaluate sources you’re thinking about using. Click on either button below to download.

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 is important to keep track of your sources with citations to avoid plagiarism . It can be helpful to make an annotated bibliography , where you compile full citation 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.

Prevent plagiarism. Run a free check.

To begin organizing your literature review’s argument and structure, be sure you 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 organizing the body of a literature review. 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 summarizing sources in order.

Try to analyze 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 organize 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.

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, you can follow these tips:

• 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 sentences to draw connections, comparisons and contrasts

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

When you’ve finished writing and revising your literature review, don’t forget to proofread thoroughly before submitting. Not a language expert? Check out Scribbr’s professional proofreading services !

This article has been adapted into lecture slides that you can use to teach your students about writing a literature review.

Scribbr slides are free to use, customize, and distribute for educational purposes.

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If you want to know more about the research process , methodology , research bias , or statistics , make sure to check out some of our other articles with explanations and examples.

• Sampling methods
• Simple random sampling
• Stratified sampling
• Cluster sampling
• Likert scales
• Reproducibility

 Statistics

• Null hypothesis
• Statistical power
• Probability distribution
• Effect size
• Poisson distribution

Research bias

• Optimism bias
• Cognitive bias
• Implicit bias
• Hawthorne effect
• Anchoring bias
• Explicit bias

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 thesis, dissertation , or research paper , in order to situate your work in relation to existing knowledge.

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

• To familiarize 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 thesis or dissertation . After the introduction , it grounds your research in a scholarly field and leads directly to your theoretical framework or methodology .

A literature review is a survey of credible sources on a topic, often used in dissertations , theses, and research papers . Literature reviews give an overview of knowledge on a subject, helping you identify relevant theories and methods, as well as gaps in existing research. Literature reviews are set up similarly to other  academic texts , with an introduction , a main body, and a conclusion .

An  annotated bibliography is a list of  source references that has a short description (called an annotation ) for each of the sources. It is often assigned as part of the research process for a  paper .  

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• 04 December 2020
• Correction 09 December 2020

How to write a superb literature review

Andy Tay is a freelance writer based in Singapore.

You can also search for this author in PubMed   Google Scholar

Literature reviews are important resources for scientists. They provide historical context for a field while offering opinions on its future trajectory. Creating them can provide inspiration for one’s own research, as well as some practice in writing. But few scientists are trained in how to write a review — or in what constitutes an excellent one. Even picking the appropriate software to use can be an involved decision (see ‘Tools and techniques’). So Nature asked editors and working scientists with well-cited reviews for their tips.

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doi: https://doi.org/10.1038/d41586-020-03422-x

Interviews have been edited for length and clarity.

Updates & Corrections

Correction 09 December 2020 : An earlier version of the tables in this article included some incorrect details about the programs Zotero, Endnote and Manubot. These have now been corrected.

Hsing, I.-M., Xu, Y. & Zhao, W. Electroanalysis 19 , 755–768 (2007).

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Ledesma, H. A. et al. Nature Nanotechnol. 14 , 645–657 (2019).

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Brahlek, M., Koirala, N., Bansal, N. & Oh, S. Solid State Commun. 215–216 , 54–62 (2015).

Choi, Y. & Lee, S. Y. Nature Rev. Chem . https://doi.org/10.1038/s41570-020-00221-w (2020).

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A necessary skill for any doctor

What causes disease, which drug is best, does this patient need surgery, and what is the prognosis? Although experience helps in answering these questions, ultimately they are best answered by evidence based medicine. But how do you assess the evidence? As a medical student, and throughout your career as a doctor, critical appraisal of published literature is an important skill to develop and refine. At medical school you will repeatedly appraise published literature and write literature reviews. These activities are commonly part of a special study module, research project for an intercalated degree, or another type of essay based assignment.

Formulating a question

Literature reviews are most commonly performed to help answer a particular question. While you are at medical school, there will usually be some choice regarding the area you are going to review.

Once you have identified a subject area for review, the next step is to formulate a specific research question. This is arguably the most important step because a clear question needs to be defined from the outset, which you aim to answer by doing the review. The clearer the question, the more likely it is that the answer will be clear too. It is important to have discussions with your supervisor when formulating a research question as his or her input will be invaluable. The research question must be objective and concise because it is easier to search through the evidence with a clear question. The question also needs to be feasible. What is the point in having a question for which no published evidence exists? Your supervisor’s input will ensure you are not trying to answer an unrealistic question. Finally, is the research question clinically important? There are many research questions that may be answered, but not all of them will …

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How to Conduct a Literature Review (Health Sciences and Beyond)

What is a literature review, traditional (narrative) literature review, integrative literature review, systematic reviews, meta-analysis, scoping review.

• Developing a Research Question
• Selection Criteria
• Database Search
• Documenting Your Search
• Organize Key Findings
• Reference Management

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Related Guides

• Systematic Reviews by Roy Brown Last Updated Oct 17, 2023 613 views this year
• Write a Literature Review by John Glover Last Updated Oct 16, 2023 3197 views this year

A literature review provides an overview of what's been written about a specific topic. There are many different types of literature reviews. They vary in terms of comprehensiveness, types of study included, and purpose. 

The other pages in this guide will cover some basic steps to consider when conducting a traditional health sciences literature review. See below for a quick look at some of the more popular types of literature reviews.

For additional information on a variety of review methods, the following article provides an excellent overview.

Grant MJ, Booth A. A typology of reviews: an analysis of 14 review types and associated methodologies. Health Info Libr J. 2009 Jun;26(2):91-108. doi: 10.1111/j.1471-1842.2009.00848.x. Review. PubMed PMID: 19490148.

• Next: Developing a Research Question >>
• Last Updated: Mar 15, 2024 12:22 PM
• URL: https://guides.library.vcu.edu/health-sciences-lit-review

How To Write a Literature Review: A Step-By-Step Guide

‍Ever felt intimidated by the thought of writing a literature review? Sounds silly, but trust us—it can be intimidating. The fear of being found lacking in academic prowess or not meeting your client’s expectations often prevents most medical writers from even attempting to write a review. But, don’t let this deter you! Learning how to write a literature review is one of the most things you can do as a medical writer.

Literature reviews are one of the easiest jobs you can give yourself as a writer. They also serve as one of the most important ones. Why? Well, because they act as gatekeepers for any scholarly work that you will produce in your vocation and throughout your medical writing career.

That said, it’s not always easy to know where to start when faced with such an intimidating task. And while there are many different types of literature reviews, they all have certain common features that make them easier to write than others

What is a literature review?

A literature review summarises the most important literature related to a particular topic. It is a synthesis of particular studies, articles, and other sources on the subject, and it serves as the basic source material for any research you will do on the same subject.

In other words, a literature review forms the basis for further research that you will do on a certain subject. A literature review is not an original work. Rather, it is a summary of other sources that you have found on your topic. As such, it’s not something you need to “write for yourself” but something that others have already written.

How to write a literature review

Now that you understand what a literature review is, let’s take a closer look at how to write one. There are a few important things to keep in mind when you’re writing your literature review.

• Select relevant sources: It is important to select relevant sources for your literature review. When you read through journals, books, and articles in search of relevance for your review, you are selecting sources that will inform the topic of your review and provide the readers of your review with relevant information.
• Find relevant context: It is important to find the relevant context that relates to your sources. What were they researching? What was the context of their research? This context will help your review readers understand more fully the information your sources provide.
• Synthesize information: Last but not least, you need to synthesize information from your sources. This includes summarizing, analysing, and weaving information from your sources to present a broader topic picture.

Things you will need for your review

• A PC: To research and write your literature review. For an online review, this may be all you need.

If you are doing a manual review of printed materials, you’ll need the following:

• Paper: If you are writing a literature review on a certain book, paper, or journal, you will need paper to write on. You can use scrap paper as well as lined paper.
• Pens: You will need a pen to set your pen down as well as a pen that is not too thick or too thin.
• Calculator: You may also need to use a calculator to perform certain calculations in your review.

Why do you need i t ?

A literature review is a very important step in the research process. Without a good literature review, you can go down many wrong paths and make incorrect conclusions.

In fact, most modern research has to start with a good literature review and then be refined into a more precise research design. This is because the research design should be the next step after selecting relevant sources for your review. When you have gathered all the relevant information on your topic, you can refine your research design and end up with a research project worth publishing.

A literature review is also essential for publishing in scholarly journals. The editors of journals have a lot of leeway when deciding whether or not they want to publish a research paper. The most common way they decide whether or not to accept a manuscript is by reading the literature review. If your literature review could explain the topic of your paper well enough, then you might just get accepted!

Checklist of things to include in your review

• Selection of the topic of your literature review: What do you want to learn about? What is the significance of this topic? Why should you write a literature review on this topic?
• Review of relevant sources: What were the most important sources you read about your topic? What did you find most relevant? What is the context that you found most relevant? What did you synthesize from these sources? What is the main conclusion you drew from your sources?
• Summary of the information: Did you summarize each source? Did you synthesize information from these sources? What is the main idea that you drew from your sources? How does this information compare to what other sources have to say about the same subject?
• Conclusions: What overall conclusion have you drawn from your sources? What did you learn from these sources? What do you recommend to others who look into this topic?
• References: Finally, you will need to include a reference list at the end of your paper with the titles of the sources you used in your literature review. Learn more about referencing list and referencing format .

We’re sure that by now, you’re convinced that writing a literature review is a great way to gain a lot of insight into your research topic. But, we want to assure you that it is possible to write a literature review without much trouble. We just need to keep these things in mind while we’re writing.

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Searching the public health & medical literature more effectively: literature review help.

• Getting Started
• Articles: Searching PubMed This link opens in a new window
• More Sources: Databases, Systematic Reviews, Grey Literature
• Organize Citations & Search Strategies
• Literature Review Help
• Need More Help?

Writing Guides, Manuals, etc.

Literature Review Tips Handouts

Write about something you are passionate about!

• About Literature Reviews (pdf)
• Literature Review Workflow (pdf)
• Search Tips/Search Operators
• Quick Article Evaluation Worksheet (docx)
• Tips for the Literature Review Workflow
• Sample Outline for a Literature Review (docx)

Ten simple rules for writing a literature review . Pautasso M. PLoS Comput Biol. 2013;9(7):e1003149. doi:10.1371/journal.pcbi.1003149

Conducting the Literature Search . Chapter 4 of Chasan-Taber L. Writing Dissertation and Grant Proposals: Epidemiology, Preventive Medicine and Biostatistics. New York: Chapman and Hall/CRC, 2014.

A step-by-step guide to writing a research paper, from idea to full manuscript . Excellent and easy to follow blog post by Dr. Raul Pacheco-Vega.

Data Extraction

Data extraction answers the question “what do the studies tell us?”

At a minimum, consider the following when extracting data from the studies you are reviewing ( source ):

• Only use the data elements relevant to your question;
• Use a table, form, or tool (such as Covidence ) for data extraction;
• Test your methods and tool for missing data elements, redundancy, consistency, clarity.

Here is a table of data elements to consider for your data extraction. (From University of York, Centre for Reviews and Dissemination).

Critical Reading

As you read articles, write notes. You may wish to create a table, answering these questions:

• What is the hypothesis?
• What is the method? Rigorous? Appropriate sample size? Results support conclusions?
• What are the key findings?
• How does this paper support/contradict other work?
• How does it support/contradict your own approach?
• How significant is this research? What is its special contribution?
• Is this research repeating existing approaches or making a new contribution?
• What are its strengths?
• What are its weaknesses/limitations?

From: Kearns, H. & Finn, J. (2017) Supervising PhD Students: A Practical Guide and Toolkit . AU: Thinkwell, p. 103.

Submitting to a Journal? First Identify Journals That Publish on Your Topic

Through Scopus

• Visit the  Scopus database.
• Search for recent articles on your research topic.
• Above the results, click “Analyze search results."
• Click in the "Documents per year by source" box.
• On the left you will see the results listed by the number of articles published on your research topic per journal.

Through Web of Science

• Visit the Web of Science database.
• In the results, click "Analyze Results" on the right hand side.
• From the drop-down menu near the top left, choose "Publication Titles."
• Change the "Minimum record count (threshold)," if desired.
• Scroll down for a table of results by journal title.
• JANE (Journal/Author Name Estimator) Use JANE to help you discover and decide where to publish an article you have authored. Jane matches the abstract of your article to the articles in Medline to find the best matching journals (or authors, or articles).
• Jot (Journal Targeter) Jot uses Jane and other data to determine journals likely to publish your article (based on title, abstract, references) against the impact metric of those journals. From Yale University.
• EndNote Manuscript Matcher Using algorithms and data from the Web of Science and Journal Citation Reports, Manuscript Matcher identifies the most relevant and impactful journals to which one may wish to submit a manuscript. Access Manuscript Matcher via EndNote X9 or EndNote 20.
• DOAJ (Directory of Open Access Journals) Journal Lookup Look up a journal title on DOAJ and find information on publication fees, aims and scope, instructions for authors, submission to publication time, copyright, and more.

Writing Help @UCB

Here is a short list of sources of writing help available to UC Berkeley students, staff, and faculty:

• Purdue OWL Excellent collection of guides on writing, including citing/attribution, citation styles, grammar and punctuation, academic writing, and much more.
• Berkeley Writing: College Writing Programs "Our philosophy includes small class size, careful attention to building your critical reading and thinking skills along with your writing, personalized attention, and a great deal of practice writing and revising." Website has a Writing Resources Database .
• Graduate Writing Center, Berkeley Graduate Division Assists graduate students in the development of academic skills necessary to successfully complete their programs and prepare for future positions. Workshops and online consultations are offered on topics such as academic writing, grant writing, dissertation writing , thesis writing , editing, and preparing articles for publication, in addition to writing groups and individual consultations.
• Nature Masterclass on Scientific Writing and Publishing For Postdocs, Visiting Scholars, and Visiting Student Researchers with active, approved appointments, and current UC Berkeley graduate students who are new to publishing or wish to refresh their skills. Part 1: Writing a Research Paper; Part 2: Publishing a Research Paper; Part 3: Writing and Publishing a Review Paper. Offered by Visiting Researcher Scholar and Postdoc Affairs (VSPA) program; complete this form to gain access.

Alternative Publishing Formats

Here is some information and tips on getting your research to a broader, or to a specialized, audience

• Creating One-Page Reports One-page reports are a great way to provide a snapshot of a project’s activities and impact to stakeholders. Summarizing key facts in a format that is easily and quickly digestible engages the busy reader and can make your project stand out. From EvaluATE .
• How to write an Op-ed (Webinar) Strategies on how to write sharp op-eds for broader consumption, one of the most important ways to ensure your analysis and research is shared in the public sphere. From the Institute for Research on Public Policy .
• 10 tips for commentary writers From UC Berkeley Media Relations’ 2017 Op-Ed writing workshop.
• Journal of Science Policy and Governance JSPG publishes policy memos, op-eds, position papers, and similar items created by students.
• Writing Persuasive Policy Briefs Presentation slides from a UCB Science Policy Group session.
• 3 Essential Steps to Share Research With Popular Audiences (Inside Higher Ed) How to broaden the reach and increase the impact of your academic writing. Popular writing isn’t a distraction from core research!

The Politics of Citation

"One of the feminist practices key to my teaching and research is a feminist practice of citation."

From The Digital Feminist Collective , this blog post emphasizes the power of citing.

"Acknowledging and establishing feminist genealogies is part of the work of producing more just forms of knowledge and intellectual practice."

Here's an exercise (docx) to help you in determining how inclusive you are when citing.

Additional Resources for Inclusive Citation Practices :

• BIPOC Scientists Citation guide (Rockefeller Univ.).
• Conducting Research through an Anti-Racism Lens (Univ. of Minnesota Libraries).
• cleanBib (Code to probabilistically assign gender and race proportions of first/last authors pairs in bibliography entries).
• Balanced Citer (Python script guesses the race and gender of the first and last authors for papers in your citation list and compares your list to expected distributions based on a model that accounts for paper characteristics).
• Read Black women's work;
• Integrate Black women into the CORE of your syllabus (in life & in the classroom);
• Acknowledge Black women's intellectual production;
• Make space for Black women to speak;
• Give Black women the space and time to breathe.
• CiteASista .
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• Last Updated: May 22, 2024 3:44 PM
• URL: https://guides.lib.berkeley.edu/publichealth/litsearch

Writing in the Health Sciences: Research and Lit Reviews

• Research and Lit Reviews
• Tables and Figures
• Citation Management
• Further Reference

What Is a Literature Review?

In simple terms, a literature review investigates the available information on a certain topic. It may be only a knowledge survey with an intentional focus. However, it is often a well-organized examination of the existing research which evaluates each resource in a systematic way. Often a lit review will involve a series of inclusion/exclusion criteria or an assessment rubric which examines the research in-depth. Below are some interesting sources to consider.

The Writing Center's Literature Reviews - UNC-Chapel Hill's writing center explains some of the key criteria involved in doing a literature review.

Literature Review vs. Systematic Review - This recent article details the difference between a literature review and a systematic review. Though the two share similar attributes, key differences are identified here.

Literature Review Steps

1. Identify a research question. For example: "Does the use of warfarin in elderly patients recovering from myocardial infarction help prevent stroke?"

2. Consider which databases might provide information for your topic. Often PubMed or CINAHL will cover a wide spectrum of biomedical issues. However, other databases and grey literature sources may specialize in certain disciplines. Embase is generally comprehensive but also specializes in pharmacological interventions.

3. Select the major subjects or ideas from your question.  Focus in on the particular concepts involved in your research. Then brainstorm synonyms and related terminology for these topics.

4. Look for the  preferred indexing terms for each concept in your question. This is especially important with databases such as PubMed, CINAHL, or Scopus where headings within the MeSH database or under the Emtree umbrella are present.  For example, the above question's keywords such as " warfarin " or "myocardial infarction" can involve related terminology or subject headings such as "anti-coagulants" or "cardiovascular disease."

5. Build your search using boolean operators. Combine the synonyms in your database using boolean operators such as AND or OR. Sometimes it is necessary to research parts of a question rather than the whole. So you might link searches for things like the preventive effects of anti-coagulants with stroke or embolism, then AND these results with the therapy for patients with cardiovascular disease.

6. Filter and save your search results from the first database (do this for all databases). This may be a short list because of your topic's limitations, but it should be no longer than 15 articles for an initial search. Make sure your list is saved or archived and presents you with what's needed to access the full text.

7. Use the same process with the next databases on your list. But pay attention to how certain major headings may alter the terminology. "Stroke" may have a suggested term of "embolism" or even "cerebrovascular incident" depending on the database.

8. Read through the material for inclusion/exclusion . Based on your project's criteria and objective, consider which studies or reviews deserve to be included and which should be discarded. Make sure the information you have permits you to go forward. 

9. Write the literature review. Begin by summarizing why your research is important and explain why your approach will help fill gaps in current knowledge. Then incorporate how the information you've selected will help you to do this. You do not need to write about all of the included research you've chosen, only the most pe rtinent.

10. Select the most relevant literature for inclusion in the body of your report. Choose the articles and data sets that are most particularly relevant to your experimental approach. Consider how you might arrange these sources in the body of your draft. 

Library Books

Call #: WZ 345 G192h 2011

ISBN #: 9780763771867

This book details a practical, step-by-step method for conducting a literature review in the health sciences. Aiming to  synthesize the information while also analyzing it, the Matrix Indexing System enables users to establish a  structured process for tracking, organizing and integrating the knowledge within a collection.

Key Research Databases

PubMed -  The premier medical database for review articles in medicine, nursing, healthcare, other related biomedical disciplines. PubMed contains over 20 million citations and can be navigated through multiple database capabilities and searching strategies.

CINAHL Ultimate - Offers comprehensive coverage of health science literature. CINAHL is particularly useful for those researching the allied disciplines of nursing, medicine, and pharmaceutical sciences.

Scopus - Database with over 12 million abstracts and citations which include peer-reviewed titles from international and Open Access journals. Also includes interactive bibliometrics and researcher profiling.

Embase - Elsevier's fully interoperable database of both Medline and Emtree-indexed articles. Embase also specializes in pharmacologic interventions.

Cochrane - Selected evidence-based medicine resources from the Cochrane Collaboration that includes peer-reviewed systematic reviews and randomized controlled trials. Access this database through OVID with TTUHSC Libraries.

DARE - Literally the Datatase of Abstracts of Reviews of Effectiveness, this collection of systematic reviews and other evidence-based research contains critical assessments from a wide variety of medical journals.

TRIP - This TRIP database is structured according to the level of evidence for its EBM content. It allows users to quickly and easily locate high-quality, accredited medical literature for clinical and research purposes.

Web of Science - Contains bibliographic articles and data from a wide variety of publications in the life sciences and other fields. Also, see this link for conducting a lit review exclusively within Web of Science.

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What is a literature review?

Systematic reviews vs literature reviews, literature reviews - articles, writing literature reviews, frequently used journal article databases.

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The literature review is the qualitative summary of evidence on a topic using informal or subjective methods to collect and interpret studies.The literature review can inform a particular research project or can result in a review article publication.

• Aaron L. Writing a literature review article. Radiol Technol. 2008 Nov-Dec; 80(12): 185-6.
• Gasparyan AY, Ayvazyan L, Blackmore H, Kitas GD. Writing a narrative biomedical review: considerations for authors, peer reviewers, and editors. Rheumatol Int. 2011 Nov; 31(11): 1409-17.
• Matharu GS, Buckley CD. Performing a literature review: a necessary skill for any doctor. Student BMJ. 2012; 20:e404. Requires FREE site registration
• Literature Reviews The Writing Center at University of North Carolina at Chapel Hill has created a succinct handout that explains what a literature review is and offer insights into the form and construction of a literature review in the humanities, social sciences, and sciences.
• Review Articles (Health Sciences) Guide Identifies the difference between a systematic review and a literature review. Connects to tools for research, writing, and publishing.

• Systematic Approaches to a Successful Literature Review by Andrew Booth; Diana Papaioannou; Anthea Sutton Call Number: Norris Medical Library, Upper Level, LB 1047.3 B725s 2012
• Documenting your search This resource provides guidance on how to document and save database search strategies.
• Cochrane Database of Systematic Reviews
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Literature Review Overview

What is a Literature Review? Why Are They Important?

A literature review is important because it presents the "state of the science" or accumulated knowledge on a specific topic. It summarizes, analyzes, and compares the available research, reporting study strengths and weaknesses, results, gaps in the research, conclusions, and authors’ interpretations.

Tips and techniques for conducting a literature review are described more fully in the subsequent boxes:

• Literature review steps
• Strategies for organizing the information for your review
• Literature reviews sections
• In-depth resources to assist in writing a literature review
• Templates to start your review
• Literature review examples

Literature Review Steps

Graphic used with permission: Torres, E. Librarian, Hawai'i Pacific University

1. Choose a topic and define your research question

• Try to choose a topic of interest. You will be working with this subject for several weeks to months.
• Ideas for topics can be found by scanning medical news sources (e.g MedPage Today), journals / magazines, work experiences, interesting patient cases, or family or personal health issues.
• Do a bit of background reading on topic ideas to familiarize yourself with terminology and issues. Note the words and terms that are used.
• Develop a focused research question using PICO(T) or other framework (FINER, SPICE, etc - there are many options) to help guide you.
• Run a few sample database searches to make sure your research question is not too broad or too narrow.
• If possible, discuss your topic with your professor. 

2. Determine the scope of your review

The scope of your review will be determined by your professor during your program. Check your assignment requirements for parameters for the Literature Review.

• How many studies will you need to include?
• How many years should it cover? (usually 5-7 depending on the professor)
• For the nurses, are you required to limit to nursing literature?

3. Develop a search plan

• Determine which databases to search. This will depend on your topic. If you are not sure, check your program specific library website (Physician Asst / Nursing / Health Services Admin) for recommendations.
• Create an initial search string using the main concepts from your research (PICO, etc) question. Include synonyms and related words connected by Boolean operators
• Contact your librarian for assistance, if needed.

4. Conduct searches and find relevant literature

• Keep notes as you search - tracking keywords and search strings used in each database in order to avoid wasting time duplicating a search that has already been tried
• Read abstracts and write down new terms to search as you find them
• Check MeSH or other subject headings listed in relevant articles for additional search terms
• Scan author provided keywords if available
• Check the references of relevant articles looking for other useful articles (ancestry searching)
• Check articles that have cited your relevant article for more useful articles (descendancy searching). Both PubMed and CINAHL offer Cited By links
• Revise the search to broaden or narrow your topic focus as you peruse the available literature
• Conducting a literature search is a repetitive process. Searches can be revised and re-run multiple times during the process.
• Track the citations for your relevant articles in a software citation manager such as RefWorks, Zotero, or Mendeley

5. Review the literature

• Read the full articles. Do not rely solely on the abstracts. Authors frequently cannot include all results within the confines of an abstract. Exclude articles that do not address your research question.
• While reading, note research findings relevant to your project and summarize. Are the findings conflicting? There are matrices available than can help with organization. See the Organizing Information box below.
• Critique / evaluate the quality of the articles, and record your findings in your matrix or summary table. Tools are available to prompt you what to look for. (See Resources for Appraising a Research Study box on the HSA, Nursing , and PA guides )
• You may need to revise your search and re-run it based on your findings.

6. Organize and synthesize

• Compile the findings and analysis from each resource into a single narrative.
• Using an outline can be helpful. Start broad, addressing the overall findings and then narrow, discussing each resource and how it relates to your question and to the other resources.
• Cite as you write to keep sources organized.
• Write in structured paragraphs using topic sentences and transition words to draw connections, comparisons, and contrasts.
• Don't present one study after another, but rather relate one study's findings to another. Speak to how the studies are connected and how they relate to your work.

Organizing Information

Options to assist in organizing sources and information :

1. Synthesis Matrix

• helps provide overview of the literature
• information from individual sources is entered into a grid to enable writers to discern patterns and themes
• article summary, analysis, or results
• thoughts, reflections, or issues
• each reference gets its own row
• mind maps, concept maps, flowcharts
• at top of page record PICO or research question
• record major concepts / themes from literature
• list concepts that branch out from major concepts underneath - keep going downward hierarchically, until most specific ideas are recorded
• enclose concepts in circles and connect the concept with lines - add brief explanation as needed

3. Summary Table

• information is recorded in a grid to help with recall and sorting information when writing
• allows comparing and contrasting individual studies easily
• purpose of study
• methodology (study population, data collection tool)

Efron, S. E., & Ravid, R. (2019). Writing the literature review : A practical guide . Guilford Press.

Literature Review Sections

• Lit reviews can be part of a larger paper / research study or they can be the focus of the paper
• Lit reviews focus on research studies to provide evidence
• New topics may not have much that has been published

* The sections included may depend on the purpose of the literature review (standalone paper or section within a research paper)

Standalone Literature Review (aka Narrative Review):

• presents your topic or PICO question
• includes the why of the literature review and your goals for the review.
• provides background for your the topic and previews the key points
• Narrative Reviews: tmay not have an explanation of methods.
• include where the search was conducted (which databases) what subject terms or keywords were used, and any limits or filters that were applied and why - this will help others re-create the search
• describe how studies were analyzed for inclusion or exclusion
• review the purpose and answer the research question
• thematically - using recurring themes in the literature
• chronologically - present the development of the topic over time
• methodological - compare and contrast findings based on various methodologies used to research the topic (e.g. qualitative vs quantitative, etc.)
• theoretical - organized content based on various theories
• provide an overview of the main points of each source then synthesize the findings into a coherent summary of the whole
• present common themes among the studies
• compare and contrast the various study results
• interpret the results and address the implications of the findings
• do the results support the original hypothesis or conflict with it
• provide your own analysis and interpretation (eg. discuss the significance of findings; evaluate the strengths and weaknesses of the studies, noting any problems)
• discuss common and unusual patterns and offer explanations
•  stay away from opinions, personal biases and unsupported recommendations
• summarize the key findings and relate them back to your PICO/research question
• note gaps in the research and suggest areas for further research
• this section should not contain "new" information that had not been previously discussed in one of the sections above
• provide a list of all the studies and other sources used in proper APA 7

Literature Review as Part of a Research Study Manuscript:

• Compares the study with other research and includes how a study fills a gap in the research.
• Focus on the body of the review which includes the synthesized Findings and Discussion

Literature Reviews vs Systematic Reviews

Systematic Reviews are NOT the same as a Literature Review:

Literature Reviews:

• Literature reviews may or may not follow strict systematic methods to find, select, and analyze articles, but rather they selectively and broadly review the literature on a topic
• Research included in a Literature Review can be "cherry-picked" and therefore, can be very subjective

Systematic Reviews:

• Systemic reviews are designed to provide a comprehensive summary of the evidence for a focused research question
• rigorous and strictly structured, using standardized reporting guidelines (e.g. PRISMA, see link below)
• uses exhaustive, systematic searches of all relevant databases
• best practice dictates search strategies are peer reviewed
• uses predetermined study inclusion and exclusion criteria in order to minimize bias
• aims to capture and synthesize all literature (including unpublished research - grey literature) that meet the predefined criteria on a focused topic resulting in high quality evidence

Literature Review Examples

• Breastfeeding initiation and support: A literature review of what women value and the impact of early discharge (2017). Women and Birth : Journal of the Australian College of Midwives
• Community-based participatory research to promote healthy diet and nutrition and prevent and control obesity among African-Americans: A literature review (2017). Journal of Racial and Ethnic Health Disparities

• Vitamin D deficiency in individuals with a spinal cord injury: A literature review (2017). Spinal Cord

Resources for Writing a Literature Review

These sources have been used in developing this guide.

Resources Used on This Page

Aveyard, H. (2010). Doing a literature review in health and social care : A practical guide . McGraw-Hill Education.

Purdue Online Writing Lab. (n.d.). Writing a literature review . Purdue University. https://owl.purdue.edu/owl/research_and_citation/conducting_research/writing_a_literature_review.html

Torres, E. (2021, October 21). Nursing - graduate studies research guide: Literature review. Hawai'i Pacific University Libraries. Retrieved January 27, 2022, from https://hpu.libguides.com/c.php?g=543891&p=3727230

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• Types of Literature Reviews
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• The Pandora's Box of Evidence Synthesis and the case for a living Evidence Synthesis Taxonomy | BMJ Evidence-Based Medicine, 2023
• Meeting the review family: exploring review types and associated information retrieval requirements | Health Information and Libraries Journal, 2019
• A typology of reviews: an analysis of 14 review types and associated methodologies | Health Information and Libraries Journal, 2009
• Conceptual recommendations for selecting the most appropriate knowledge synthesis method to answer research questions related to complex evidence | Journal of Clinical Epidemiology, 2016
• Methods for knowledge synthesis: an overview | Heart & Lung: The Journal of Critical Care, 2014
• Not sure what type of review to conduct? Brief descriptions of each type plus tools to help you decide

• Ten simple rules for writing a literature review | PLoS Computational Biology, 2013
• The Purpose, Process, and Methods of Writing a Literature Review | AORN Journal. 2016
• Why, When, Who, What, How, and Where for Trainees Writing Literature Review Articles. | Annals of Biomed Engineering, 2019
• So You Want to Write a Narrative Review Article? | Journal of Cardiothoracic and Anesthesia, 2021
• An Introduction to Writing Narrative and Systematic Reviews - Tasks, Tips and Traps for Aspiring Authors | Heart, Lung, and Circulation, 2018

• The Literature Review: A Foundation for High-Quality Medical Education Research | Journal of Graduate Medical Education, 2016
• Writing an effective literature review : Part I: Mapping the gap | Perspectives on Medical Education, 2018
• Writing an effective literature review : Part II: Citation technique | Perspectives on Medical Education, 2018
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JAY SIWEK, M.D., MARGARET L. GOURLAY, M.D., DAVID C. SLAWSON, M.D., AND ALLEN F. SHAUGHNESSY, PHARM.D.

Am Fam Physician. 2002;65(2):251-258

Traditional clinical review articles, also known as updates, differ from systematic reviews and meta-analyses. Updates selectively review the medical literature while discussing a topic broadly. Nonquantitative systematic reviews comprehensively examine the medical literature, seeking to identify and synthesize all relevant information to formulate the best approach to diagnosis or treatment. Meta-analyses (quantitative systematic reviews) seek to answer a focused clinical question, using rigorous statistical analysis of pooled research studies. This article presents guidelines for writing an evidence-based clinical review article for American Family Physician . First, the topic should be of common interest and relevance to family practice. Include a table of the continuing medical education objectives of the review. State how the literature search was done and include several sources of evidence-based reviews, such as the Cochrane Collaboration, BMJ's Clinical Evidence , or the InfoRetriever Web site. Where possible, use evidence based on clinical outcomes relating to morbidity, mortality, or quality of life, and studies of primary care populations. In articles submitted to American Family Physician , rate the level of evidence for key recommendations according to the following scale: level A (randomized controlled trial [RCT], meta-analysis); level B (other evidence); level C (consensus/expert opinion). Finally, provide a table of key summary points.

American Family Physician is particularly interested in receiving clinical review articles that follow an evidence-based format. Clinical review articles, also known as updates, differ from systematic reviews and meta-analyses in important ways. 1 Updates selectively review the medical literature while discussing a topic broadly. An example of such a topic is, “The diagnosis and treatment of myocardial ischemia.” Systematic reviews comprehensively examine the medical literature, seeking to identify and synthesize all relevant information to formulate the best approach to diagnosis or treatment. Examples are many of the systematic reviews of the Cochrane Collaboration or BMJ's Clinical Evidence compendium. Meta-analyses are a special type of systematic review. They use quantitative methods to analyze the literature and seek to answer a focused clinical question, using rigorous statistical analysis of pooled research studies. An example is, “Do beta blockers reduce mortality following myocardial infarction?”

The best clinical review articles base the discussion on existing systematic reviews and meta-analyses, and incorporate all relevant research findings about the management of a given disorder. Such evidence-based updates provide readers with powerful summaries and sound clinical guidance.

In this article, we present guidelines for writing an evidence-based clinical review article, especially one designed for continuing medical education (CME) and incorporating CME objectives into its format. This article may be read as a companion piece to a previous article and accompanying editorial about reading and evaluating clinical review articles. 1 , 2 Some articles may not be appropriate for an evidence-based format because of the nature of the topic, the slant of the article, a lack of sufficient supporting evidence, or other factors. We encourage authors to review the literature and, wherever possible, rate key points of evidence. This process will help emphasize the summary points of the article and strengthen its teaching value.

Topic Selection

Choose a common clinical problem and avoid topics that are rarities or unusual manifestations of disease or that have curiosity value only. Whenever possible, choose common problems for which there is new information about diagnosis or treatment. Emphasize new information that, if valid, should prompt a change in clinical practice, such as the recent evidence that spironolactone therapy improves survival in patients who have severe congestive heart failure. 3 Similarly, new evidence showing that a standard treatment is no longer helpful, but may be harmful, would also be important to report. For example, patching most traumatic corneal abrasions may actually cause more symptoms and delay healing compared with no patching. 4

Searching the Literature

When searching the literature on your topic, please consult several sources of evidence-based reviews ( Table 1 ) . Look for pertinent guidelines on the diagnosis, treatment, or prevention of the disorder being discussed. Incorporate all high-quality recommendations that are relevant to the topic. When reviewing the first draft, look for all key recommendations about diagnosis and, especially, treatment. Try to ensure that all recommendations are based on the highest level of evidence available. If you are not sure about the source or strength of the recommendation, return to the literature, seeking out the basis for the recommendation.

In particular, try to find the answer in an authoritative compendium of evidence-based reviews, or at least try to find a meta-analysis or well-designed randomized controlled trial (RCT) to support it. If none appears to be available, try to cite an authoritative consensus statement or clinical guideline, such as a National Institutes of Health Consensus Development Conference statement or a clinical guideline published by a major medical organization. If no strong evidence exists to support the conventional approach to managing a given clinical situation, point this out in the text, especially for key recommendations. Keep in mind that much of traditional medical practice has not yet undergone rigorous scientific study, and high-quality evidence may not exist to support conventional knowledge or practice.

Patient-Oriented vs. Disease-Oriented Evidence

With regard to types of evidence, Shaughnessy and Slawson 5 – 7 developed the concept of Patient-Oriented Evidence that Matters (POEM), in distinction to Disease-Oriented Evidence (DOE). POEM deals with outcomes of importance to patients, such as changes in morbidity, mortality, or quality of life. DOE deals with surrogate end points, such as changes in laboratory values or other measures of response. Although the results of DOE sometimes parallel the results of POEM, they do not always correspond ( Table 2 ) . 2 When possible, use POEM-type evidence rather than DOE. When DOE is the only guidance available, indicate that key clinical recommendations lack the support of outcomes evidence. Here is an example of how the latter situation might appear in the text: “Although prostate-specific antigen (PSA) testing identifies prostate cancer at an early stage, it has not yet been proved that PSA screening improves patient survival.” (Note: PSA testing is an example of DOE, a surrogate marker for the true outcomes of importance—improved survival, decreased morbidity, and improved quality of life.)

Evaluating the Literature

Evaluate the strength and validity of the literature that supports the discussion (see the following section, Levels of Evidence). Look for meta-analyses, high-quality, randomized clinical trials with important outcomes (POEM), or well-designed, nonrandomized clinical trials, clinical cohort studies, or case-controlled studies with consistent findings. In some cases, high-quality, historical, uncontrolled studies are appropriate (e.g., the evidence supporting the efficacy of Papanicolaou smear screening). Avoid anecdotal reports or repeating the hearsay of conventional wisdom, which may not stand up to the scrutiny of scientific study (e.g., prescribing prolonged bed rest for low back pain).

Look for studies that describe patient populations that are likely to be seen in primary care rather than subspecialty referral populations. Shaughnessy and Slawson's guide for writers of clinical review articles includes a section on information and validity traps to avoid. 2

Levels of Evidence

Readers need to know the strength of the evidence supporting the key clinical recommendations on diagnosis and treatment. Many different rating systems of varying complexity and clinical relevance are described in the medical literature. Recently, the third U.S. Preventive Services Task Force (USPSTF) emphasized the importance of rating not only the study type (RCT, cohort study, case-control study, etc.), but also the study quality as measured by internal validity and the quality of the entire body of evidence on a topic. 8

While it is important to appreciate these evolving concepts, we find that a simplified grading system is more useful in AFP . We have adopted the following convention, using an ABC rating scale. Criteria for high-quality studies are discussed in several sources. 8 , 9 See the AFP Web site ( www.aafp.org/afp/authors ) for additional information about levels of evidence and see the accompanying editorial in this issue discussing the potential pitfalls and limitations of any rating system.

Level A (randomized controlled trial/meta-analysis): High-quality randomized controlled trial (RCT) that considers all important outcomes. High-quality meta-analysis (quantitative systematic review) using comprehensive search strategies.

Level B (other evidence): A well-designed, nonrandomized clinical trial. A nonquantitative systematic review with appropriate search strategies and well-substantiated conclusions. Includes lower quality RCTs, clinical cohort studies, and case-controlled studies with non-biased selection of study participants and consistent findings. Other evidence, such as high-quality, historical, uncontrolled studies, or well-designed epidemiologic studies with compelling findings, is also included.

Level C (consensus/expert opinion): Consensus viewpoint or expert opinion.

Each rating is applied to a single reference in the article, not to the entire body of evidence that exists on a topic. Each label should include the letter rating (A, B, C), followed by the specific type of study for that reference. For example, following a level B rating, include one of these descriptors: (1) nonrandomized clinical trial; (2) nonquantitative systematic review; (3) lower quality RCT; (4) clinical cohort study; (5) case-controlled study; (6) historical uncontrolled study; (7) epidemiologic study.

Here are some examples of the way evidence ratings should appear in the text:

“To improve morbidity and mortality, most patients in congestive heart failure should be treated with an angiotensin-converting enzyme inhibitor. [Evidence level A, RCT]”

“The USPSTF recommends that clinicians routinely screen asymptomatic pregnant women 25 years and younger for chlamydial infection. [Evidence level B, non-randomized clinical trial]”

“The American Diabetes Association recommends screening for diabetes every three years in all patients at high risk of the disease, including all adults 45 years and older. [Evidence level C, expert opinion]”

When scientifically strong evidence does not exist to support a given clinical recommendation, you can point this out in the following way:

“Physical therapy is traditionally prescribed for the treatment of adhesive capsulitis (frozen shoulder), although there are no randomized outcomes studies of this approach.”

Format of the Review

Introduction.

The introduction should define the topic and purpose of the review and describe its relevance to family practice. The traditional way of doing this is to discuss the epidemiology of the condition, stating how many people have it at one point in time (prevalence) or what percentage of the population is expected to develop it over a given period of time (incidence). A more engaging way of doing this is to indicate how often a typical family physician is likely to encounter this problem during a week, month, year, or career. Emphasize the key CME objectives of the review and summarize them in a separate table entitled “CME Objectives.”

The methods section should briefly indicate how the literature search was conducted and what major sources of evidence were used. Ideally, indicate what predetermined criteria were used to include or exclude studies (e.g., studies had to be independently rated as being high quality by an established evaluation process, such as the Cochrane Collaboration). Be comprehensive in trying to identify all major relevant research. Critically evaluate the quality of research reviewed. Avoid selective referencing of only information that supports your conclusions. If there is controversy on a topic, address the full scope of the controversy.

The discussion can then follow the typical format of a clinical review article. It should touch on one or more of the following subtopics: etiology, pathophysiology, clinical presentation (signs and symptoms), diagnostic evaluation (history, physical examination, laboratory evaluation, and diagnostic imaging), differential diagnosis, treatment (goals, medical/surgical therapy, laboratory testing, patient education, and follow-up), prognosis, prevention, and future directions.

The review will be comprehensive and balanced if it acknowledges controversies, unresolved questions, recent developments, other viewpoints, and any apparent conflicts of interest or instances of bias that might affect the strength of the evidence presented. Emphasize an evidence-supported approach or, where little evidence exists, a consensus viewpoint. In the absence of a consensus viewpoint, you may describe generally accepted practices or discuss one or more reasoned approaches, but acknowledge that solid support for these recommendations is lacking.

In some cases, cost-effectiveness analyses may be important in deciding how to implement health care services, especially preventive services. 10 When relevant, mention high-quality cost-effectiveness analyses to help clarify the costs and health benefits associated with alternative interventions to achieve a given health outcome. Highlight key points about diagnosis and treatment in the discussion and include a summary table of the key take-home points. These points are not necessarily the same as the key recommendations, whose level of evidence is rated, although some of them will be.

Use tables, figures, and illustrations to highlight key points, and present a step-wise, algorithmic approach to diagnosis or treatment when possible.

Rate the evidence for key statements, especially treatment recommendations. We expect that most articles will have at most two to four key statements; some will have none. Rate only those statements that have corresponding references and base the rating on the quality and level of evidence presented in the supporting citations. Use primary sources (original research, RCTs, meta-analyses, and systematic reviews) as the basis for determining the level of evidence. In other words, the supporting citation should be a primary research source of the information, not a secondary source (such as a nonsystematic review article or a textbook) that simply cites the original source. Systematic reviews that analyze multiple RCTs are good sources for determining ratings of evidence.

The references should include the most current and important sources of support for key statements (i.e., studies referred to, new information, controversial material, specific quantitative data, and information that would not usually be found in most general reference textbooks). Generally, these references will be key evidence-based recommendations, meta-analyses, or landmark articles. Although some journals publish exhaustive lists of reference citations, AFP prefers to include a succinct list of key references. (We will make more extensive reference lists available on our Web site or provide links to your personal reference list.)

You may use the following checklist to ensure the completeness of your evidence-based review article; use the source list of reviews to identify important sources of evidence-based medicine materials.

Checklist for an Evidence-Based Clinical Review Article

The topic is common in family practice, especially topics in which there is new, important information about diagnosis or treatment.

The introduction defines the topic and the purpose of the review, and describes its relevance to family practice.

A table of CME objectives for the review is included.

The review states how you did your literature search and indicates what sources you checked to ensure a comprehensive assessment of relevant studies (e.g., MEDLINE, the Cochrane Collaboration Database, the Center for Research Support, TRIP Database).

Several sources of evidence-based reviews on the topic are evaluated ( Table 1 ) .

Where possible, POEM (dealing with changes in morbidity, mortality, or quality of life) rather than DOE (dealing with mechanistic explanations or surrogate end points, such as changes in laboratory tests) is used to support key clinical recommendations ( Table 2 ) .

Studies of patients likely to be representative of those in primary care practices, rather than subspecialty referral centers, are emphasized.

Studies that are not only statistically significant but also clinically significant are emphasized; e.g., interventions with meaningful changes in absolute risk reduction and low numbers needed to treat. (See http://www.cebm.net/index.aspx?o=1116 .) 11

The level of evidence for key clinical recommendations is labeled using the following rating scale: level A (RCT/meta-analysis), level B (other evidence), and level C (consensus/expert opinion).

Acknowledge controversies, recent developments, other viewpoints, and any apparent conflicts of interest or instances of bias that might affect the strength of the evidence presented.

Highlight key points about diagnosis and treatment in the discussion and include a summary table of key take-home points.

Use tables, figures, and illustrations to highlight key points and present a step-wise, algorithmic approach to diagnosis or treatment when possible.

Emphasize evidence-based guidelines and primary research studies, rather than other review articles, unless they are systematic reviews.

The essential elements of this checklist are summarized in Table 3 .

Siwek J. Reading and evaluating clinical review articles. Am Fam Physician. 1997;55:2064-2069.

Shaughnessy AF, Slawson DC. Getting the most from review articles: a guide for readers and writers. Am Fam Physician. 1997;55:2155-60.

Pitt B, Zannad F, Remme WJ, Cody R, Castaigne A, Perez A, et al. The effect of spironolactone on morbidity and mortality in patients with severe heart failure. N Engl J Med. 1999;341:709-17.

Flynn CA, D'Amico F, Smith G. Should we patch corneal abrasions? A meta-analysis. J Fam Pract. 1998;47:264-70.

Slawson DC, Shaughnessy AF, Bennett JH. Becoming a medical information master: feeling good about not knowing everything. J Fam Pract. 1994;38:505-13.

Shaughnessy AF, Slawson DC, Bennett JH. Becoming an information master: a guidebook to the medical information jungle. J Fam Pract. 1994;39:489-99.

Slawson DC, Shaughnessy AF. Becoming an information master: using POEMs to change practice with confidence. Patient-oriented evidence that matters. J Fam Pract. 2000;49:63-7.

Harris RP, Helfand M, Woolf SH, Lohr KN, Mulrow CD, Teutsch SM, et al. Methods Work Group, Third U.S. Preventive Services Task Force. Current methods of the U.S. Preventive Services Task Force. A review of the process. Am J Prev Med. 2001;20(3 suppl):21-35.

CATbank topics: levels of evidence and grades of recommendations. Retrieved November 2001, from: http://www.cebm.net/ .

Saha S, Hoerger TJ, Pignone MP, Teutsch SM, Helfand M, Mandelblatt JS. for the Cost Work Group of the Third U.S. Preventive Services Task Force. The art and science of incorporating cost effectiveness into evidence-based recommendations for clinical preventive services. Am J Prev Med. 2001;20(3 suppl):36-43.

Evidence-based medicine glossary. Retrieved November 2001, from: http://www.cebm.net/index.aspx?o=1116 .

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Literature review

Literature reviews are a way of identifying what is already known about a research area and what the gaps are. To do a literature review, you will need to identify relevant literature, often through searching academic databases, and then review existing literature. Most often, you will do the literature review at the beginning of your research project, but it is iterative, so you may choose to change the literature review as you move through your project.

Searching the literature

The University of Melbourne Library has some resources about searching the literature. Leonie spoke about how she met with a librarian about searching the literature. You may also want to meet face-to-face with a librarian or attend a class at the library to learn more about literature searching. When you search the literature, you may find journal articles, reports, books and other materials.

Filing, categorising and managing literature

In order to manage the literature you have identified through searches, you may choose to use a reference manager. The University of Melbourne has access to RefWorks and Endnote. Further information about accessing this software is available through the University of Melbourne Library .

Writing a literature review

The purpose of the literature review is to identify what is already known about a particular research area and critically analyse prior studies. It will also help you to identify any gaps in the research and situate your research in what is already known about a particular topic.

• Aveyard, H. (2010). Doing a literature review in health and social care: A practical guide . London, UK: McGraw-Hill Education. Retrieved from Proquest https://ebookcentral.proquest.com/lib/unimelb/detail.action?docID=771406
• Reeves, S., Koppel, I., Barr, H., Freeth, D., Hammick, M. (2002). Twelve tips for undertaking a systematic review. Medical Teacher . 24(4), 358-363 .
• Grant, M.J. and Booth, A. (2009). A typology of reviews: an analysis of 14 review types and associated methodologies. Health Information & Libraries Journal .
• Jesson, J., & Lacey, F. (2006). How to do (or not to do) a critical literature review. Pharmacy Education , 6(2), 139-148 .
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Medical Devices

How Do You Write a Literature Review for Clinical Research?

Use DistillerSR to produce CER and PER literature reviews in an efficient, audit-ready, and compliant way.

Conducting literature reviews is a crucial aspect of the medical device regulatory process. If you’re writing a clinical evaluation report (CER), you’ll need to collate and critically appraise the available evidence through a literature review. In this article, we’ll outline the basic steps involved in writing a CER literature review and discuss a few tips that will help make the process easier for you. Ultimately, MEDDEV 2.7/1 revision 4 remains the premier guideline on best practices for writing clinical evaluation reports.

How To Write a Literature Review for Clinical Research

Step 1: craft a good research question.

The first step in writing a literature review is to formulate an appropriate research question. This will guide your search for relevant literature by helping you narrow down your focus to exactly what you need. Research questions should be focused and not too broad, to ensure availability of a concentrated number of supporting research studies.

To write a good research question, you need to consider the following elements:

• What is the problem or issue that you’re trying to address?
• What are the key concepts or terms that you need to define?
• Who are the key stakeholders involved?
• What is the time frame for your review?

Upon careful consideration of these elements, you can start to develop your research question. For example, let’s say your medical device is a new type of pacemaker. Your research question might be, “What is the clinical effectiveness of this new pacemaker compared to existing pacemakers?”

To create a more precise research question, it’s best to follow the PICO framework. According to the PICO framework, your research question should contain:

• P: Patient population or problem
• I: Intervention
• C: Comparison

Using the PICO framework, your research question might be worded as, “In patients over fifty with heart failure, what is the clinical effectiveness of this new pacemaker compared to existing pacemakers?”

Now that you have a substantial and focused research question, you can move on to the next step.

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Step 2: Search for Relevant Literature

The next step is to search for relevant literature for your review. There are a number of ways to do this, but the most effective approach is to start with a systematic literature search. This involves using online databases to find all of the studies that meet your predefined inclusion and exclusion criteria.

Some of the most popular databases for medical device literature searches are PubMed and Embase. To conduct a search, you’ll need to use keywords and Boolean operators. Keywords are the words or phrases that describe your topic. Boolean operators are the words like “and,” “or,” and “not” that you can use to combine or exclude keywords in your search.

For example, let’s say you’re looking for studies on the clinical effectiveness of a pacemaker. Your keywords might be: “clinical effectiveness,” “pacemaker,” and “heart failure.” Your Boolean operators might be: “and,” “or,” and “not.”

To find studies that are specifically about the clinical effectiveness of a particular pacemaker, you could use the following search string in PubMed: ((clinical effectiveness) AND (pacemaker) AND (heart failure)) NOT ((animal study) OR (in vitro))

This search string would find all of the studies conducted on the clinical effectiveness of pacemakers in heart failure patients, and it would exclude any studies carried out on animal models or in vitro experiments.

Another important aspect is the exclusion criteria. Exclusion criteria are the characteristics of a study that would make it ineligible for inclusion in your literature review. For example, you might want to exclude studies that are not about human subjects, or you might want to exclude studies that are not published in peer-reviewed journals.

However, you must keep a record of all the excluded articles to comply with regulations. As a result, making sure exclusions are recorded systemically is critical, yet challenging. One method to do so is to create a separate “Excluded Studies” spreadsheet where you list all of the studies that you’ve excluded and why they were excluded. This will not only make it easier to keep track of your excluded studies, but it will also help you write the results later on.

Step 3: Appraise the Data

Once you’ve found all of the relevant studies, it’s time to appraise them. This means critically assessing each study to determine its usefulness, applicability, positive and negative points, and credibility. There are a number of ways to appraise studies, but one of the most popular methods is the GRADE approach.

To appraise a study using the GRADE approach, you’ll need to look at the study’s design, data, and results. You’ll also need to assess the quality of the evidence and make a judgment about the overall strength of the evidence.

The GRADE approach is a comprehensive and systematic technique to appraise studies, but it can be time-consuming. So, if you’re short on time, you should consider using our literature review tool, which reduces review times by 35% to 50% by automating every step of the process so you can enter the clinical investigation phase sooner.

3 Reasons to Connect

Defining the Role of Authors and Contributors

Page Contents

• Why Authorship Matters
• Who Is an Author?
• Non-Author Contributors
• Artificial Intelligence (AI)-Assisted Technology

1. Why Authorship Matters

Authorship confers credit and has important academic, social, and financial implications. Authorship also implies responsibility and accountability for published work. The following recommendations are intended to ensure that contributors who have made substantive intellectual contributions to a paper are given credit as authors, but also that contributors credited as authors understand their role in taking responsibility and being accountable for what is published.

Editors should be aware of the practice of excluding local researchers from low-income and middle-income countries (LMICs) from authorship when data are from LMICs. Inclusion of local authors adds to fairness, context, and implications of the research. Lack of inclusion of local investigators as authors should prompt questioning and may lead to rejection.

Because authorship does not communicate what contributions qualified an individual to be an author, some journals now request and publish information about the contributions of each person named as having participated in a submitted study, at least for original research. Editors are strongly encouraged to develop and implement a contributorship policy. Such policies remove much of the ambiguity surrounding contributions, but leave unresolved the question of the quantity and quality of contribution that qualify an individual for authorship. The ICMJE has thus developed criteria for authorship that can be used by all journals, including those that distinguish authors from other contributors.

2. Who Is an Author?

The ICMJE recommends that authorship be based on the following 4 criteria:

• Substantial contributions to the conception or design of the work; or the acquisition, analysis, or interpretation of data for the work; AND
• Drafting the work or reviewing it critically for important intellectual content; AND
• Final approval of the version to be published; AND
• Agreement to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.

In addition to being accountable for the parts of the work done, an author should be able to identify which co-authors are responsible for specific other parts of the work. In addition, authors should have confidence in the integrity of the contributions of their co-authors.

All those designated as authors should meet all four criteria for authorship, and all who meet the four criteria should be identified as authors. Those who do not meet all four criteria should be acknowledged—see Section II.A.3 below. These authorship criteria are intended to reserve the status of authorship for those who deserve credit and can take responsibility for the work. The criteria are not intended for use as a means to disqualify colleagues from authorship who otherwise meet authorship criteria by denying them the opportunity to meet criterion #s 2 or 3. Therefore, all individuals who meet the first criterion should have the opportunity to participate in the review, drafting, and final approval of the manuscript.

The individuals who conduct the work are responsible for identifying who meets these criteria and ideally should do so when planning the work, making modifications as appropriate as the work progresses. We encourage collaboration and co-authorship with colleagues in the locations where the research is conducted. It is the collective responsibility of the authors, not the journal to which the work is submitted, to determine that all people named as authors meet all four criteria; it is not the role of journal editors to determine who qualifies or does not qualify for authorship or to arbitrate authorship conflicts. If agreement cannot be reached about who qualifies for authorship, the institution(s) where the work was performed, not the journal editor, should be asked to investigate. The criteria used to determine the order in which authors are listed on the byline may vary, and are to be decided collectively by the author group and not by editors. If authors request removal or addition of an author after manuscript submission or publication, journal editors should seek an explanation and signed statement of agreement for the requested change from all listed authors and from the author to be removed or added.

The corresponding author is the one individual who takes primary responsibility for communication with the journal during the manuscript submission, peer-review, and publication process. The corresponding author typically ensures that all the journal’s administrative requirements, such as providing details of authorship, ethics committee approval, clinical trial registration documentation, and disclosures of relationships and activities are properly completed and reported, although these duties may be delegated to one or more co-authors. The corresponding author should be available throughout the submission and peer-review process to respond to editorial queries in a timely way, and should be available after publication to respond to critiques of the work and cooperate with any requests from the journal for data or additional information should questions about the paper arise after publication. Although the corresponding author has primary responsibility for correspondence with the journal, the ICMJE recommends that editors send copies of all correspondence to all listed authors.

When a large multi-author group has conducted the work, the group ideally should decide who will be an author before the work is started and confirm who is an author before submitting the manuscript for publication. All members of the group named as authors should meet all four criteria for authorship, including approval of the final manuscript, and they should be able to take public responsibility for the work and should have full confidence in the accuracy and integrity of the work of other group authors. They will also be expected as individuals to complete disclosure forms.

Some large multi-author groups designate authorship by a group name, with or without the names of individuals. When submitting a manuscript authored by a group, the corresponding author should specify the group name if one exists, and clearly identify the group members who can take credit and responsibility for the work as authors. The byline of the article identifies who is directly responsible for the manuscript, and MEDLINE lists as authors whichever names appear on the byline. If the byline includes a group name, MEDLINE will list the names of individual group members who are authors or who are collaborators, sometimes called non-author contributors, if there is a note associated with the byline clearly stating that the individual names are elsewhere in the paper and whether those names are authors or collaborators.

3. Non-Author Contributors

Contributors who meet fewer than all 4 of the above criteria for authorship should not be listed as authors, but they should be acknowledged. Examples of activities that alone (without other contributions) do not qualify a contributor for authorship are acquisition of funding; general supervision of a research group or general administrative support; and writing assistance, technical editing, language editing, and proofreading. Those whose contributions do not justify authorship may be acknowledged individually or together as a group under a single heading (e.g. "Clinical Investigators" or "Participating Investigators"), and their contributions should be specified (e.g., "served as scientific advisors," "critically reviewed the study proposal," "collected data," "provided and cared for study patients," "participated in writing or technical editing of the manuscript").

Because acknowledgment may imply endorsement by acknowledged individuals of a study’s data and conclusions, editors are advised to require that the corresponding author obtain written permission to be acknowledged from all acknowledged individuals.

Use of AI for writing assistance should be reported in the acknowledgment section.

4. Artificial Intelligence (AI)-Assisted Technology

At submission, the journal should require authors to disclose whether they used artificial intelligence (AI)-assisted technologies (such as Large Language Models [LLMs], chatbots, or image creators) in the production of submitted work. Authors who use such technology should describe, in both the cover letter and the submitted work in the appropriate section if applicable, how they used it. For example, if AI was used for writing assistance, describe this in the acknowledgment section (see Section II.A.3). If AI was used for data collection, analysis, or figure generation, authors should describe this use in the methods (see Section IV.A.3.d). Chatbots (such as ChatGPT) should not be listed as authors because they cannot be responsible for the accuracy, integrity, and originality of the work, and these responsibilities are required for authorship (see Section II.A.1). Therefore, humans are responsible for any submitted material that included the use of AI-assisted technologies. Authors should carefully review and edit the result because AI can generate authoritative-sounding output that can be incorrect, incomplete, or biased. Authors should not list AI and AI-assisted technologies as an author or co-author, nor cite AI as an author. Authors should be able to assert that there is no plagiarism in their paper, including in text and images produced by the AI. Humans must ensure there is appropriate attribution of all quoted material, including full citations.

Next: Disclosure of Financial and Non-Financial Relationships and Activities, and Conflicts of Interest

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