How to Write a Literature Review
Learn how to write top-notch lit reviews, plus review types, and how to conduct them effectively
As a medical writer, you'll likely be called on to write a literature review or be asked to review the literature as a foundation for whatever project you’re working on.
However, it’s easy to get sucked into a rabbit hole, especially if your objectives aren’t clear and you don’t have a robust search strategy. We explored this a little in EP48 of Write Medicine.
Picture this: You're a medical writer tasked with developing a CME grant proposal on the latest advances in treating a particular disease state. Your client wants a comprehensive literature review to provide the foundation for the educational design and establish the need for the initiative.
You dive into PubMed, searching for relevant studies. Hours later, you're feeling overwhelmed and frustrated. You're finding a lot of irrelevant papers and you're worried you're missing key studies. The deadline is looming and you're not sure you'll have time to sift through everything and synthesize the findings in a meaningful way.
If this sounds familiar, fear not: today we'll explore how to efficiently find the most relevant, high-quality studies to inform your work so you can feel confident you're producing comprehensive reviews.
So, let's explore what a literature review is, why we do them, types, and most importantly, how to do a literature review.
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What is a Literature Review?
A literature review is a comprehensive overview and critical analysis of the published research on a particular topic. It involves summarizing what is known and unknown about a topic but goes beyond summarizing the literature.
A good review usually synthesizes the available research to identify patterns, gaps, and new insights that help us think critically about that topic.
Literature reviews also provide context for research, whether we're talking about clinical or biomedical research, research to support a quality improvement intervention, or research to support a grant application in CME.
However, literature reviews come in more than one flavor. They vary in methodology, rigor, and depth depending on the project you're working on.
Why Do We Write Literature Reviews?
In medical writing, literature reviews can be valuable because they help you see where your project fits into a broader scholarly conversation.
Whether or not you see yourself as engaging in scholarly work, a literature review can help you articulate clear goals and show that you've done your due diligence. They can also communicate relevant results, showing you want to be part of the conversation.
“Imagine yourself joining a conversation at a social event. After you hang about eavesdropping to get the drift of what's being said (the conversational equivalent of the literature review), you join the conversation with a contribution that signals your shared interest in the topic, your knowledge of what's already been said, and your intention.” -Lorelei Lingard
Types of Medical Writing Literature Reviews Serve
Knowing how to do a literature review is a useful skill because they're needed in so many areas of medical writing. Let's review some of the uses of literature reviews, from the health technology industry to grant proposals and patient education materials.
In all these cases, rigorous, up-to-date literature reviews synthesize the best available evidence to inform key medical writing deliverables like slide decks, needs assessments, research protocols, or decision aids.
The type of review will depend on the specific use case and audience, but they all aim to distill meaningful insights from the large volume of biomedical literature to support evidence-based decision-making.
Clinical Practice Guidelines
You may work with clinical practice guideline groups that need support in searching and synthesizing literature on particular topics. Literature reviews provide the evidence base for developing trustworthy guidelines and identify areas of consensus or disagreement to guide clinical practice recommendations.
Grant Proposals
Grant writers identify gaps in current knowledge and practice to justify the need for new studies or interventions. Reviews establish the background and rationale for the proposed research or approach.
Research Articles
If you help authors develop their work for submission to peer-reviewed journals, you might be tasked with reviewing the relevant literature. Your search and synthesis can help to frame the introduction and orient readers to the current state of knowledge about the topic and to expand the discussion section..
Ideally, authors should conduct a lit review before embarking on a study, but that doesn't always happen. One of my first projects in CME was working with an author group to help them contextualize an outcomes project by reviewing the literature on the topic. I searched and synthesized the peer-reviewed literature, identified key points of comparison, and crafted insights to sharpen the discussion.
Health Technology Assessments
If you work in the health technology assessment field or in coverage decisions, literature reviews are essential for synthesizing evidence on the safety, efficacy, and cost-effectiveness of medical interventions to inform policies on coverage and appropriate use of technologies.
CME
In CME, if you are working on a grant proposal, needs or landscape assessment, literature reviews are valuable to curate the latest research findings on a disease state or therapeutic area. A thorough review lays the foundation for designing education that will update and upskill health professionals.
Patient Decision Aids
Literature reviews gather evidence on benefits and harms to support patient education efforts. They help create balanced, evidence-based tools for patient decision-making and shared decision-making practices.
Medical Affairs
Literature reviews will help you analyze the competitive landscape and identify unmet clinical needs to support strategic planning for product development and commercialization.
Types of Literature Reviews
Narrative (Traditional) reviews
These provide a broad, critical analysis of the published research on a topic. Narrative subtypes include state-of-the-art reviews (for instance, the Journal of the American College of Cardiology includes this type on an annual basis), or critical reviews, like a Lancet Commission. In a CME/CPD context, use cases might include:
Providing historical context or tracing the evolution of a topic in CME/CPD
Critiquing assumptions or proposing new research directions
Synthesizing qualitative research or integrating theories relevant to CME/CPD
Systematic reviews
This type of review aims to answer a specific, narrowly focused research question and follows a rigorous, transparent protocol to identify, appraise, and synthesize all relevant studies on a focused question.
For instance, PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) is a standard reporting guideline that documents the entire review process. In a CME/CPD context, a systematic review might be appropriate to:
Evaluate the effectiveness of specific educational interventions or strategies
Compare outcomes across different educational approaches
Inform evidence-based decision-making in CME/CPD
Scoping reviews
A scoping review explores the extent and nature of research on a topic and aims to map the extent, range, and nature of research activity in a field.
Scoping reviews often include not only the peer-reviewed literature, but also the gray literature, expert commentary, internal data, and social/behavioral sciences insights. In a CME/CPD context, a scoping review might be appropriate to:
Identify gaps in knowledge or practice to inform CME/CPD interventions
Provide background and rationale for educational initiatives
Explore the full scope of a topic, including clinical, behavioral, and contextual factors that drive gaps
Realist reviews
Realist reviews examine how complex interventions work across contexts and explore what works, for whom, and under what circumstances. In a CME/CPD context, a realist review might be appropriate to:
Understand the contextual factors influencing the success of CME/CPD interventions
Identify key mechanisms and outcomes of educational initiatives in different settings
Generate theories or causal explanations to guide future CME/CPD design and implementation
Other types of reviews include meta-analyses, integrative reviews, mixed-methods reviews, and more. The key is to select the review type that aligns with your research methods. Download our full typology table here.
Conducting a Literature Review
Now that we know more about what a literature review is and all of the different types of reviews we can conduct, how do we do a literature review in a time-effective way? Let's discuss how to streamline your process, find relevant information, and make your literature reviews stronger.
Strategic Literature Search
Define and Refine Research Objectives
Start by defining the research question or your objectives. This clarity will guide your search strategy. Objectives usually start with a question that could be narrow or broad, also known as a foreground or background question.
A foreground question could be, what is the general clinical or behavioral problem? For whom is this a problem? In what contexts does ithe problemoccur? What are the consequences of this problem?hat are some educational ways to solve the problem? This approach is a variation of the PICO framework (Problem/Population, Intervention, Comparison, Outcome).
If you'd like to keep your search strategy more general with background questions, you can start with foundational knowledge about your disorder, disease, patient population, policy issue, or whatever it is you're writing about broadly.
Other search strategy frameworks you may find helpful include SPIDER (Sample, Phenomenon of Interest, Design, Evaluation, Research Type); SPICE (Setting, Perspective, Intervention/phenomenon of Interest, Comparison, Evaluation); or PEO (Population, Exposure, Outcome).
As you begin your search, whether you're casting a wide net or starting with a narrow focus, remember that searching is an iterative process that involves refinement of your strategy as you go based on the results you're getting. Database filters are a helpful tool for refining results by year, article type, and age group.
Use a Combination of Searches
It can help to use a combination of keyword, subject heading, and index term searches and include synonyms, spelling variations, and related terms to capture a wide range of potentially relevant sources. You can also use Boolean operators like AND, OR, and NOT to combine and refine terms.
Start with MeSH
Start with MeSH (Medical Subject Headings) terms before moving on to semantic terms. MeSH terms are a comprehensive controlled vocabulary used for indexing and cataloging journal articles and books in the life sciences.
MeSH is hierarchical with broader "descriptor" terms and narrower "subheading" or "qualifier" terms that can be combined to describe the subject of an article precisely.
Indexers at the National Library of Medicine assign MeSH terms to MEDLINE/PubMed records and provide a standardized way to search and retrieve relevant literature. Here are a couple of examples:
Heart Disease - This broad MeSH term encompasses more specific conditions like "Arrhythmias, Cardiac" and "Atrial Fibrillation".
Lung Neoplasms - This MeSH term covers various synonyms like "lung cancer", "lung tumor", and "pulmonary cancer"
Databases
These search strategies are especially helpful with PubMed, but you don’t have to limit yourself to PubMed. Comprehensive searches across multiple databases using keywords and subject headings are helpful for finding all relevant sources.
Here are some of the Databases and Search Engines that might be relevant to your search.
PubMed/MEDLINE: is a free database that primarily includes the MEDLINE database of references and abstracts on life sciences and biomedical topics. It is maintained by the United States National Library of Medicine (NLM) at the National Institutes of Health.
MEDLINE is the NLM's journal citation database that provides over 31 million references to biomedical and life sciences journal articles dating back to 1946.
MEDLINE includes citations from more than 5,200 scholarly journals that are reviewed and selected by the NLM's Literature Selection Technical Review Committee.
The key differences between PubMed and MEDLINE are:
MEDLINE is the underlying database of journal citations, while PubMed is the free public interface that provides access to MEDLINE and additional content.
PubMed includes MEDLINE citations as well as additional records for in-process articles, out-of-scope articles from MEDLINE journals, and author manuscripts from NIH-funded research.
MEDLINE citations use the NLM's controlled Medical Subject Headings (MeSH) vocabulary for indexing, while PubMed allows searching across a broader range of fields and content types.
Embase: Embase is a major biomedical and pharmacological literature database that provides extensive international coverage, daily updates, and specialized indexing to support research, drug development, and evidence-based practice across the medical field
CINAHL: The Cumulative Index to Nursing and Allied Health Literature is a bibliographic database that indexes and abstracts articles from journals in the fields of nursing, allied health, biomedicine, and healthcare
PsycINFO: Database covering psychological, social, behavioral, and health sciences literature
Google Scholar: Broad search engine for scholarly literature across various disciplines
Cochrane Library: Collection of databases containing high-quality evidence for healthcare decision-making
Health Technology Assessment Database: a comprehensive, publicly accessible repository of HTA reports and resources from organizations around the world, providing a centralized source of information to support evidence-based healthcare decision-making
ECRI Guidelines Trust is an interactive guideline portal with access to current, evidence-based clinical practice guidelines
Gray Literature Sources
You may need to include unpublished or other gray literature sources. These could include reports from foundations or non-profit organizations, as well as medical news items or policy reports from government agencies.
For instance, if you were a medical writer doing a literature search for clinical practice gaps in selecting therapies for a particular tumor type in oncology, you might review the following:
Guidelines and consensus statements
Government and regulatory agency publications
U.S. Food and Drug Administration (FDA) reports and guidance
Centers for Medicare & Medicaid Services (CMS) coverage policies
The Health Technology Assessment (HTA) Database - This centralized repository of HTA reports from around the world could identify gaps in the real-world implementation of oncology interventions.
Industry and professional association publications, including pharmaceutical and biotech company whitepapers and oncology nursing or pharmacy association publications.
Conference proceedings and abstracts:
Patient advocacy and professional organization websites, which often publish patient and provider surveys, whitepapers, and educational materials
Clinical trial registries (ClinicalTrials.gov, EUC Clinical Trials Register provide information on ongoing and completed trials, which can reveal areas of unmet need or emerging therapies).
Supplementary Search Techniques
Supplementary search techniques that can make your database search more robust include scanning the reference list of key studies or articles, conducting forward citation searches, searching for related articles, and contacting subject matter experts.
Document Your Search
You’ll want to carefully document the search process, including the databases searched, search terms used, and any limits or filters applied.
This helps you evaluate the completeness of your research for a given project and provide a rationale for your team or client.
For example, in CME, some education providers want to see an account of your research methodology and search terms.
Tools and Resources
The first thing to do to organize your findings is to create a structured table to synthesize and report the results. You can create a spreadsheet for literature search documentation or use this one created by New York University Libraries.
I also love Endnote, whichI've used for years. It’s a powerful reference management platform that integrates with both Word and Google Docs, automatically formats the citations and generates a properly formatted bibliography at the end of the document, and supports collaboration and sharing.
Another great tool is Zotero. This free, open-source software helps you collect, organize, and cite research sources. It also offers browser extensions for easy online research and allows you to create collections and sub-collections to organize search results from different databases, as well as identify and merge duplicate records.
For note-taking, I suggest Evernote, a Cloud-based, cross-platform app that allows you to create notes, tags, and notebooks. It supports a variety of media, including text, images, PDFs, and audio files.
Here are some other popular note-taking apps:
Microsoft OneNote. Part of the Microsoft Office Suite, this app allows you to create and organize notes. It supports handwriting, drawing, and audio recording and offers a web clipper for saving online content.
Notion. An all-in-one workspace for notes, tasks, wikis, and databases. It offers a flexible block-based structure for creating and organizing content.
RoamResearch. A note-taking and knowledge management tool that focused on networked thought. It allows you to create bidirectional links between notes, creating a personal wiki with powerful search and filtering capabilities.
Obsidian. Similarly, this note-taking app allows you to create a network of connected notes with bidirectional links and powerful search features.
When all's said and done, the most powerful tool you have is the ability to conduct a well-done literature review that advances knowledge and informs evidence-based practice. By understanding the different review typologies, following best practices for comprehensive searching and critical analysis, and leveraging key tools and resources, you'll be well on your way to producing insightful, impactful reviews.
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