For a dissertation, the literature review is usually Chapter 2 — and it's the chapter committees scrutinize hardest, because it has to do more than list sources. It must synthesise, evaluate, and map existing knowledge, then land on the specific gap your study fills. This guide walks through database searching, organisational structures, synthesis technique, and how to write the gap statement that justifies your research.
A literature review is a critical, structured overview of published research on a specific topic. Its purpose is not to describe every paper you read — it is to build a coherent argument about what is known, how it is known, where the evidence conflicts, and what remains unresolved.
In a dissertation, the literature review serves three functions at once: it demonstrates that you know the field, it builds the theoretical or conceptual framework your study sits inside, and it justifies — through the gap it identifies — why your specific study needs to exist. Committees read it looking for all three, not just a survey of who-said-what.
A scoped literature review covers a well-defined question. Before opening a database, answer these questions:
Use the PICO or SPIDER framework to define your scope precisely — PICO (Population, Intervention/Issue, Comparison, Outcome) for quantitative topics, SPIDER (Sample, Phenomenon of Interest, Design, Evaluation, Research type) for qualitative ones. Either helps you construct database search strings efficiently.
For a dissertation literature review, use peer-reviewed databases — not Google. Key databases:
| Database | Best For |
|---|---|
| ProQuest Dissertations & Theses | Finding related dissertations in your field |
| Web of Science | Cross-disciplinary, high-impact journals, citation tracking |
| Scopus | Broad coverage across disciplines |
| ERIC | Education research |
| PubMed / CINAHL | Health, nursing, medicine |
| PsycINFO | Psychology and behavioral science |
| Google Scholar | Broad coverage — use for citation chaining, not primary searching |
Build a search string using Boolean operators:
A broad search may return thousands of papers. Screen in stages:
Use a reference manager. Zotero, Mendeley, or EndNote allow you to import search results directly, remove duplicates, store PDFs, and generate citations automatically. Start using one before your first search — not after you've accumulated 200 unsorted PDFs.
Our dissertation specialists research, synthesise, and write full Chapter 2 literature reviews with documented search strategy and APA/Harvard referencing.
How you organise the literature depends on what makes the argument clearest. Three common structures:
Group sources by the themes, concepts, or variables they address — not by who wrote them or when. Best for most dissertation literature reviews because it synthesises rather than lists, and maps cleanly onto a theoretical framework.
Organise by how the field has evolved over time — useful when the development of a theory or body of practice is itself the story.
Group studies by the research design or method used — quantitative vs qualitative, experimental vs correlational. Useful when you want to compare what different methods reveal about the same question.
The most common failure in literature reviews is writing summaries (one source per paragraph) rather than synthesising (multiple sources combined to make a point). Examiners reward synthesis.
Chen et al. (2022) found that mentorship reduced turnover. Rodriguez et al. (2023) also found that mentorship reduced turnover. Kim and Park (2023) conducted a study on mentorship.
Multiple recent studies confirm that structured mentorship reduces early-career turnover (Chen et al., 2022; Kim & Park, 2023; Rodriguez et al., 2023), though effect sizes vary substantially with mentorship duration and organizational context.
A good literature review does not treat all sources as equally valid. You should evaluate:
After synthesising what is known, you must identify what is not known or not yet resolved. This gap justifies your study and should lead directly into your problem statement and research questions in Chapter 1. Common types of gaps:
State the gap explicitly: "Despite extensive research on mentorship and retention broadly, no study has examined how mentorship structure specifically affects turnover among newly licensed nurses in rural hospital settings. This study addresses that gap."
There is no fixed number, but most full dissertation literature review chapters cite 60–150+ sources, with a strong preference for sources published in the last 5–10 years (with foundational/theoretical works exempted). Check your program's handbook — some specify a minimum.
Other dissertations are commonly cited, especially to show how your study fits into a line of research. Reports and grey literature are usually acceptable in moderation but shouldn't dominate — peer-reviewed journal articles should make up the bulk of your reference list.
Many programs require a distinct subsection (sometimes its own chapter) laying out the theoretical or conceptual framework, separate from the thematic review of prior studies. Check your dissertation handbook — see our theoretical framework guide for how the two relate.