How to Write a Literature Review
Quick answer: A literature review critically synthesises existing research on your topic to show what is known, what is contested, and where the gap lies. Structure it thematically (not source-by-source): group studies by theme, compare and evaluate them, and lead the reader towards your research question.
What a literature review is (and isn’t)
A literature review is not a list of summaries. It is a critical, thematic synthesis that evaluates the evidence, identifies patterns and disagreements, and justifies why your research is needed.
Step 1 — Search systematically
- Use academic databases (Google Scholar, JSTOR, PubMed, your library).
- Record search terms, dates and inclusion criteria.
- Prioritise peer-reviewed and recent sources.
Step 2 — Evaluate each source
For each study, note its argument, method, findings and limitations. Ask: is it credible, relevant and current? Weaker or dated sources can still be included to show how thinking has developed.
Step 3 — Organise by theme
Group sources into themes or debates rather than reviewing them one by one. Within each theme, compare studies, highlight agreement and conflict, and build towards the gap your research addresses.
Step 4 — Write and signpost
- Open with the scope and structure of the review.
- Use clear thematic headings.
- Synthesise (‘several studies show..., however...’) rather than describe.
- End by stating the gap and your resulting research question.
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Frequently Asked Questions
How long should a literature review be?
It depends on the assignment — often 20–30% of a dissertation. Quality of synthesis matters more than length.
Should I organise it by source or by theme?
By theme. A source-by-source structure reads as a list of summaries and scores poorly; thematic organisation shows critical synthesis.
How many sources do I need?
There is no fixed number; enough to cover the key debates in your field. Depth and relevance matter more than quantity.
What is a research gap?
A question or area that existing research hasn’t adequately answered. Identifying it justifies your own study.
Is a literature review the same as a systematic review?
No. A systematic review follows a strict, reproducible protocol (e.g. PRISMA); a standard literature review is narrative and thematic.