How To Do A Literature Review For A Medical Research Paper | Step-By-Step Playbook

What A Good Medical Literature Review Does

In medicine, readers want clarity, traceable methods, and honest limits. A well built review does four things. It defines a precise question and scope. It finds the right evidence without missing the landmark trials. It judges study quality with fair tools. It writes the story of the evidence so clinicians can use it.

Doing A Literature Review For A Medical Research Paper: Steps

Clarify The Question With A Clinically Grounded Frame

Pick a frame that fits your topic, such as PICO for treatments, PECO for exposures, or SPIDER for qualitative work. Name the population with tight wording and any care setting. Spell out the index treatment or exposure and the main comparator. Choose primary and secondary outcomes that echo clinical decisions, like survival, pain scores, or readmissions.

Pick The Review Type And Scope

Decide early whether you will write a systematic review, a scoping review, or a targeted narrative. A systematic review fits best when you can predefine criteria, apply dual screening, and keep methods reproducible. A scoping review maps broad fields and often feeds a later systematic review. A lean narrative may fit a narrow method paper or an early background section, but still use clear search logic.

Create A Protocol You Can Defend

Write a short protocol before you search. State the question, eligibility rules, primary outcomes, time window, languages, and study designs. Plan how you will handle preprints, conference abstracts, and grey sources. Describe the number of screeners, how conflicts will be settled, and which bias tools you will use. If the review is systematic, register the plan in a public registry such as PROSPERO; journals and readers value the transparency.

Design A Search Strategy That Balances Recall And Precision

Start with the natural language terms that clinicians use. Expand with synonyms and spelling variants. Then add controlled vocabulary. In PubMed, MeSH gives strong coverage of medical topics and helps you catch indexed records; the PubMed Help pages explain filters, field tags, and the search builder. Combine terms with AND, OR, and NOT. Test and refine until a set of known sentinel papers appears near the top.

Pick the right mix of sources. PubMed includes MEDLINE and beyond; Embase adds strong pharmacology and device indexing; CENTRAL captures trials; CINAHL indexes nursing and allied health; Web of Science and Scopus bring citation chasing. Note any date or language limits and justify them. Save every full search string, the date run, and the number of hits.

Grey Literature And Trial Registries

Search outside journals when the topic calls for it. Trial registries such as ClinicalTrials.gov and WHO ICTRP flag ongoing or unpublished work. Theses, conference books, and agency reports can show signals that have not reached print. Use targeted site searches and citation chasing to reach these pockets. Record sources and dates as you would for databases, and state which items entered screening.

Run Searches, Export, And Deduplicate

Export complete records with abstracts and identifiers. Use a reference manager or screening tool to merge libraries and remove duplicates by title, author, year, and DOI. Keep a log of counts per database and the rules you used. The log will feed your PRISMA flow.

Screen Titles And Abstracts, Then Full Texts

Train screeners on a pilot set until agreement looks stable. Run blinded dual screening on titles and abstracts with quick rules for inclusion. Move to full texts with the same two-reviewer model. Record reasons for exclusion with a controlled list such as wrong population, wrong design, wrong outcome, or duplicate cohort.

Extract Data With A Reproducible Form

Draft a form in a spreadsheet or web tool. Include study ID, design, setting, patient traits, exposure or treatment details, comparator, follow-up, and all outcomes with units. Add notes for effect size data, adjustments, and funding or conflicts. Pilot the form on three to five studies and revise once to remove friction. Then extract in pairs or with audit checks on a sample.

Assess Risk Of Bias With Fit-For-Purpose Tools

Match tools to design. RoB 2 fits randomized trials. ROBINS-I fits non-randomized comparative studies. QUADAS-2 fits diagnostic accuracy. NOS can rate cohort and case-control designs in brief. AMSTAR 2 assesses published reviews if you plan an umbrella review. Document judgments by domain and back each call with a short quote or page mark from the source paper.

Synthesize The Evidence And Handle Heterogeneity

Plan how you will group outcomes and time points. A narrative synthesis may suit mixed designs or patchy data. If trials look close enough, compute pooled effects. Choose fixed or random effects based on clinical and statistical spread. Report I² with a short note on meaning. Inspect forest plots and study weights. Run leave-one-out checks and, when counts allow, test for small-study effects with funnel plots or regression tests.

Write Methods And Results With Item-By-Item Clarity

Map each method and result to a clear reporting item. The PRISMA 2020 update supplies a 27-item checklist, an abstract checklist, and a flow diagram that readers expect to see. Describe the role of each database, the exact strings, the dates searched, the screening model, the bias tools, and any meta-analytic choices. Show counts at each stage with a PRISMA diagram.

How To Conduct A Medical Research Paper Literature Review With Rigor

Quality Checks That Save Revisions

Look for unit errors, swapped denominators, and double counting the same cohort. Cross-check sample sizes across tables and text. Confirm that inclusion dates and settings match between abstract and full text. Recalculate a random sample of effect sizes from raw numbers. If a paper is missing needed data, write to the authors with a tight request and a deadline.

Common Pitfalls And Clean Fixes

Over-tight keywords miss sentinel trials, so build term lists before you search. Filters can hide eligible records, so avoid quick clicks on language or human limits unless justified. Single-reviewer screening raises error risk, so keep two people in the loop. Vague outcomes lead to weak synthesis, so define units and time windows up front. Mixing adjusted and unadjusted effects can skew a pool, so align effect types or run planned subgroup analyses.

Time-Saving Habits For Busy Teams

Write while you work. Drop methods text into a living document as soon as you lock a step. Keep a folder with search logs, extraction sheets, and bias judgments named by date. Use email templates for author contact and data requests. Assign one person to guard decision rules and one to guard files. Short, regular huddles beat long, rare meetings.

Data Management, Reproducibility, And Sharing

Name files with dates and versions. Store raw exports, deduplicated sets, excluded lists, and included sets. Preserve the exact code used for any meta-analysis. Post the protocol and the final extraction sheet in a stable repository when policies allow. Hidden steps erode trust; shared steps invite reuse and updates.

Statistical Choices You Should State

Explain why an outcome is continuous or binary and how you handled change from baseline. State which effect measure you used, such as risk ratio, odds ratio, mean difference, or standardized mean difference. Name the model, the estimator, and the software. Define your heterogeneity thresholds and any rules for subgroup or sensitivity work. Report how you handled zero cells, small trials, and missing standard deviations.

When To Extend The Methods

Some topics need extra steps. Network meta-analysis compares many treatments at once. Diagnostic reviews need a paired accuracy plot and a hierarchical model. Prognostic reviews track risk scores and calibration. If you move into these zones, lean on methods texts and senior statisticians, and keep each choice traceable.

Write For Clinicians And Editors

Lead each section with the bottom line, then show how you got there. Use short sentences and concrete numbers. Keep tables tight and label units. In limits, name what you could not do and why it may change the take-home point. Avoid inflated language. Show how the findings fit bedside choices or policy steps.

Reporting And Submission Checklist

Confirm that your abstract lists the question, data sources, dates, and main results. In the main text, include full search strings in an appendix. Attach the PRISMA flow diagram. Share bias tables by domain. State funding and conflicts. If you used a handbook or checklist, cite it and provide a link. The Cochrane Handbook remains a trusted methods source across many designs, and PRISMA sets clear expectations for what to report, from search strings to bias tables to study flow. Include the checklist as an appendix so editors can verify each item quickly.

Peer Review Prep And Responses

Before submission, ask a colleague to screen the flow diagram, the bias tables, and one forest plot. Invite one person outside your field to read the abstract for plain meaning. When reviews arrive, reply with a numbered list. Quote each point, state the change you made, and point to the page and line. If you disagree, give a short, polite reason and back it with a method source.

Ethics, Equity, And Patient-Centered Reading

Call out gaps that affect groups by age, sex, ancestry, language, or access to care when the data allow. Flag trials stopped early or funded by vested parties. Use plain language for any patient-facing summary. Share data dictionaries so others can reuse your work for updates and local adaptations.

Final Polish: Flow, Style, And Figures

Open the introduction with the clinical problem and the clear need for this review. In methods, write in past tense and keep one idea per sentence. In results, start with study flow, then study traits, then main outcomes. Use figures to carry weight: a PRISMA diagram for flow, a forest plot for magnitude, and a table that aligns populations and outcomes. Keep captions rich enough to stand alone.