A narrative literature review synthesises what is known about a topic and argues towards your research question; a systematic review answers a single tightly defined question by searching, screening and appraising the evidence against a protocol written in advance. Most UK undergraduate dissertations need the first. The second is a research method in its own right, with a workload to match.
The confusion is understandable, because departments use “literature review” loosely — sometimes meaning a chapter inside an empirical dissertation, sometimes meaning a whole dissertation with no primary data collection. Those are different things with different rules, and choosing wrongly costs weeks.
What is a narrative literature review?
It is the chapter, usually your second, that establishes what is already known and why your question is worth asking. Its job is argumentative. You are not cataloguing studies; you are building a case that ends in a gap only your project can fill.
A good one is organised by theme or debate, not by study. If your paragraphs begin “Smith (2019) found…”, “Jones (2021) found…”, you have written an annotated bibliography. If they begin “Two competing explanations have been offered for this effect…”, you have written a review.
There is no requirement to find every relevant paper, and no requirement to document your search. You choose what is relevant and defend the choice implicitly through the quality of the argument.
What is a systematic review?
A systematic review is a research method that treats the published literature as its dataset. The defining features are that the question is fixed in advance, the search is exhaustive and reproducible, the inclusion and exclusion criteria are pre-specified, screening is documented at every stage, and the quality of included studies is formally appraised.
Two reference points govern the field. Reporting is guided by the PRISMA 2020 statement — Page and colleagues, published in the BMJ in 2021 (372:n71) — which sets out what a review must report, including the flow of records from identification through screening to inclusion. Methods, in health and related fields, are guided by the Cochrane Handbook for Systematic Reviews of Interventions, currently version 6.5 (2024), edited by Julian Higgins and James Thomas.
Note what those two documents are for. PRISMA tells you how to report a review; it is a reporting guideline, not a licence. Producing a PRISMA flow diagram does not make a review systematic, and markers who know the field can tell the difference immediately.
How do the two actually differ?
| Feature | Narrative literature review | Systematic review |
|---|---|---|
| Question | Broad, may evolve as you read | Fixed and narrow before you search |
| Protocol | None | Written and ideally registered in advance |
| Search | Purposive; undocumented | Exhaustive, multi-database, fully reproducible |
| Inclusion criteria | Implicit | Pre-specified and applied consistently |
| Screening | Not recorded | Recorded at every stage, ideally by two people |
| Quality appraisal | Informal, in the prose | Formal, using a named tool |
| Reproducibility | Not expected | Essential |
| Where it sits | A chapter within a dissertation | Can be the entire dissertation |
Why is a full systematic review usually the wrong choice at undergraduate level?
Three practical reasons, none of them about your ability.
- Double screening. Methodological standards expect two independent reviewers to screen records, with disagreements resolved by a third. As a lone undergraduate you do not have that, and the honest write-up has to concede it as a limitation that undercuts the method’s central claim.
- Database access. An exhaustive search means several databases plus grey literature. Your institutional subscriptions may not cover what the protocol requires, and you cannot report a search you could not run.
- Time. Screening several thousand titles and abstracts, then full texts, then appraising each included study, is a serious workload before you write a single word of synthesis. On a one-semester project it routinely overruns.
None of this makes systematic review impossible as an undergraduate project — some departments run them well, with narrow scope and explicit supervision. But it should be a deliberate choice made with your supervisor, not a default reached because it sounded rigorous.
What is the middle option?
A structured or scoping review: you borrow the transparency of systematic method without claiming exhaustiveness. In practice that means you state your search terms, name the databases and the date range, give your inclusion and exclusion criteria, report how many records you screened and how many you kept, and appraise quality informally but consistently.
This is very often what departments mean when they advertise a “literature-based dissertation”, and it is the sweet spot: markedly more rigorous than a narrative review, honest about what it is, and deliverable in the time you have. Crucially, you describe it accurately — as a structured review — rather than labelling it systematic.
How do you know which one your department wants?
Ask, and read three things before you do: your module handbook, the marking rubric, and one or two past dissertations if your department keeps them. The rubric is the most revealing. If it awards marks for “search strategy” and “quality appraisal”, a systematic or structured review is expected. If it awards marks for “critical synthesis” and “identification of a gap”, a narrative review is expected.
Whichever you are writing, the review has to end by earning your research question — and if you are doing primary research, the methods that follow must be consistent with the argument the review just made. That link is explicit in a well-built methodology chapter: a review that generates testable propositions calls for a deductive design, and one that opens up meanings calls for a qualitative one.
What does a quality appraisal tool actually do?
It gives you a consistent set of questions to ask of every included study, so that “this study is weak” becomes a defensible judgement rather than an impression. Different designs need different tools — randomised trials, observational studies and qualitative research are appraised on different criteria — so pick the one that matches the studies you are including, name it, and apply it to every study rather than only the ones you distrust.
The output is not a score you average. It is a description of where the evidence base is strong and where it is thin, which then shapes how confidently you can state your conclusions.
Practical next step
Decide the type first, write the criteria second, search third. Doing it in any other order produces a review that has to be rebuilt. If you know which type you need and want to get the chapter moving, you can draft and structure it in Tesify around your own sources and your own argument — 100% written by you, with the organisation handled.
Frequently asked questions
Can an undergraduate dissertation be entirely a literature review?
Yes, in many UK departments, and it is a legitimate route — especially where ethical approval for primary data collection would be difficult. It is not an easier option, though: without primary data, the analysis of the literature has to carry the whole project.
Do I need to register a protocol for an undergraduate review?
Usually not, and most undergraduate projects are not registered. Writing a protocol for yourself is still worthwhile, because it stops you adjusting your inclusion criteria once you can see which results they produce.
Is PRISMA compulsory if I use a flow diagram?
If you present a PRISMA flow diagram you are signalling that you followed the reporting guideline, so you should report the other relevant items too. If you only want to show how many records you screened, call it a screening flow diagram and describe it in your own terms.
How many studies should a structured review include?
There is no fixed number, and a small, well-appraised set is better than a large, poorly examined one. What matters is that your inclusion criteria were applied consistently and that the number you ended with follows from them rather than from when you got tired.
What is the difference between a scoping review and a systematic review?
A scoping review maps what evidence exists on a broad topic and how it has been studied; a systematic review answers a specific question about what the evidence shows. Scoping reviews do not usually appraise study quality, because breadth rather than verdict is the point.
Can I include grey literature in an undergraduate review?
Yes, and in policy, education and management topics you often should — reports, theses and official publications may hold most of the relevant evidence. State that you searched it and how, since grey literature is not indexed like journal articles.
Should the literature review chapter come before or after the methodology?
Before, in the conventional UK structure, because the methods have to answer the gap the review identifies. Write them in that order too; a methodology drafted before the review is settled almost always needs rewriting.
My supervisor called my review “descriptive”. What does that mean?
That you are reporting studies rather than putting them in conversation. The fix is structural: reorganise the chapter around themes or disagreements rather than around individual papers, and make each paragraph state a claim that the cited studies then support or complicate.