How to write a literature review for a thesis

What a literature review is for

A review does three jobs. It shows that you know the field. It places your study in relation to existing work. And it identifies a gap, a disagreement or an untested assumption that your research addresses. A chapter that reports what each author said, one after another, does the first job only.

Step 1: define the scope

Write down the question the review must answer, the concepts involved, and the limits: period, geography, language, discipline and type of source. Limits you can state are limits you can defend.

Step 2: search systematically

• List keywords and synonyms for each concept, and combine them.
• Search the databases your discipline uses, not only a general search engine.
• Follow citations backwards (the reference lists of key papers) and forwards (later work that cites them).
• Keep a log of where you searched, with which terms, and when. You will need it for the methodology or for a systematic review.

Step 3: read with a matrix

Record each source in a table as you read. A simple matrix makes patterns visible and makes writing far faster.

Step 4: organise by theme, not by author

Group the sources by the debates, concepts or methods that matter for your question. Other workable structures are chronological (how an idea developed), methodological (how it has been studied) and theoretical (which frameworks have been used). Choose the one that leads most directly to your gap.

Step 5: write synthesis

Each paragraph should make a point about the literature and support it with several sources. Compare them: where they agree, where they conflict, and why. A useful test is to read only the first sentence of every paragraph. If those sentences alone tell the story of the field and end at your gap, the structure works.

Step 6: state the gap

End the chapter with a short, explicit statement of what is missing and how your study responds. This statement should match the research questions in your introduction word for word in substance.

Common mistakes

• Summarising sources in sequence with no comparison.
• Relying on older or secondary sources when the primary work is available.
• Reporting findings without noting the method or the limits of the study.
• Leaving the gap implied.
• Citing a work you have not read, from someone else's description of it.

Sources and further reading

For systematic reviews, the PRISMA statement sets out what to report. The EQUATOR Network collects reporting guidelines by study type.