How to Write a Literature Review

A literature review is a systematic process of reading and synthesis that shows what is known about a topic, what is debated and what remains unknown. In a thesis it is not a list of sources; it is a map that explains why your research question matters and where your study connects to the field.

1.What a literature review should achieve

• Introduce the key concepts, theories and models in your area
• Compare and synthesise the findings of previous studies
• Expose inconsistencies, debates and the research gap
• Justify your methods and measurement instruments
• Build the foundation for comparing your findings in the discussion

2.Step 1: Define scope and keywords

Extract the core concepts from your research question and build a list of synonyms for each. In health sciences, using MeSH terms significantly improves search precision. Also decide on a time window (for example, the last ten years), language criteria and publication types (articles, theses, reviews).

3.Step 2: Choose the right databases

• Web of Science and Scopus: multidisciplinary, ideal for citation tracking
• PubMed / MEDLINE: medicine, nursing, physiotherapy and health sciences
• ERIC: education
• PsycINFO: psychology and behavioural sciences
• Google Scholar: broad coverage but limited filtering
• ProQuest Dissertations & Theses: graduate theses worldwide

4.Step 3: Build a search strategy

Boolean operators are the backbone of any search. AND combines concepts and narrows results, OR combines synonyms and broadens them, and NOT excludes unwanted terms. Quotation marks search for exact phrases and the asterisk searches word stems. Example: ("burnout" OR "emotional exhaustion") AND (nurs*) AND ("sleep quality"). Record your search strings, dates and hit counts in a table; you will need them for your methods section and your defense.

5.Step 4: Screen your sources

Your first search may return hundreds or thousands of results. Screen in stages: titles first, then abstracts, then full texts. Write your inclusion and exclusion criteria before you start. If you are conducting a systematic review, you will be expected to report this process with a PRISMA flow diagram; applying similar discipline to a standard thesis review increases its credibility.

6.Step 5: Read and take structured notes

Use the same template for every source: authors and year, aim, sample, design, instruments, key findings, limitations and relevance to your study. Collecting this in a spreadsheet or synthesis matrix makes it much easier to compare sources by theme when you write. A reference manager such as Zotero, Mendeley or EndNote will save you hours of manual formatting later.

7.Step 6: Synthesise by theme

A weak literature review summarises sources one by one: “Smith (2019) found this. Jones (2020) found that.” A strong review makes sources talk to each other around themes: “Most studies examining sleep quality and burnout report a moderate positive association (Smith, 2019; Jones, 2020), but how shift type shapes this relationship remains contested (Lee, 2021).” Synthesis shows similarities, differences and gaps in the same paragraph.

8.Step 7: Structure the chapter

1. Open with a short paragraph describing the scope and organisation of the chapter.
2. Explain the theoretical framework and key concepts.
3. Synthesise the relevant studies under thematic headings.
4. Discuss contradictory findings and methodological limitations.
5. Close with a paragraph summarising the gap your study will fill.

9.Common mistakes

• Summarising sources chronologically or alphabetically
• Relying only on old sources or on a single language
• Citing secondary sources as if they were primary
• Padding the chapter with sources unrelated to the research question
• Applying the citation style (e.g. APA 7) inconsistently
• Using long direct quotations instead of your own synthesis