How many sources should a nursing literature review have? There is no reliable universal number. A short course assignment, a dissertation chapter and a systematic review ask different questions and use evidence differently. Start with the assessment brief, then judge whether your sources are sufficient to cover the question, compare relevant findings and support your conclusions.
The Open University advises that a literature review should select a range of references appropriate to the project’s length and scope rather than reward a long list for its own sake (The Open University, n.d.). Swansea University similarly advises students to seek their academic lead’s expectation for their particular review (Swansea University, n.d.). An online claim that every nursing review needs a fixed number can therefore be misleading.
What determines the source count in a nursing literature review?
| Factor | What to check | Effect on your plan |
|---|---|---|
| Assessment requirements | Minimum or maximum sources, word limit, date range and required source types. | Follow explicit rules first; ask the module team if they conflict. |
| Question and scope | Population, nursing issue, setting and outcomes or experiences. | A tightly focused question may need fewer directly relevant studies than a broad survey of several fields. |
| Review type | Narrative, integrative, scoping or systematic review. | Systematic reviews report a transparent search and selection process; their included-study count is an outcome of eligibility decisions. |
| Available evidence | How many credible, eligible studies actually address the question. | A sparse field may justify a small evidence base and a careful limitations discussion. |
| Depth of analysis | Whether you can compare methods, findings and limitations rather than list citations. | Adding sources that receive no meaningful analysis does not strengthen the review. |
For a dissertation, also distinguish sources used in the literature-review chapter from references cited across the entire dissertation. A total in the final reference list does not tell you how thoroughly the review chapter examines its core evidence.
Check the brief before searching for a number
Look for an explicit minimum, a required number of primary studies, a publication-date rule or a limit on books and websites. Some tasks ask for a selected set of papers to appraise; others expect a broader thematic chapter. University of Arizona Libraries recommends checking whether a project has a minimum or maximum number of sources while defining its scope (University of Arizona Libraries, n.d.).
Write down the rule exactly. “At least ten peer-reviewed articles” is different from “ten references,” and neither automatically describes how many studies a systematic search will find. If the brief does not state a number, avoid inventing one as a requirement. Ask the tutor about the expected depth and look at the marking criteria.
Count the evidence that answers your nursing question
A source earns its place by doing a job. It might establish the size or nature of a practice concern, provide a theoretical perspective, report an intervention outcome, describe patient experience or challenge a conclusion drawn from another study. Harvard’s guide to evaluating sources asks readers to consider author expertise, purpose, scope and currency where relevant (Harvard College Writing Center, n.d.).
For example, a review on patients’ understanding of medication changes at discharge could require studies of communication, patient experience and implementation. A general article on hospital discharge may help set context but cannot replace evidence about the precise nursing question. Count the studies that actually inform your analysis, not every item saved in a reference manager.
Use an evidence map to spot gaps and unnecessary sources
Before deciding that you have enough, create a small matrix. List each source against the themes and functions it supports. The example below is illustrative; its rows are planning categories, not a suggested number of studies.
| Theme | Evidence needed | Question to ask |
|---|---|---|
| What patients understand | Relevant patient-experience studies. | Are several perspectives represented, or does one small study carry the claim? |
| How nurses explain changes | Studies of communication processes or interventions. | Can you compare settings, methods and findings? |
| Practical constraints | Implementation evidence or credible guidance. | Do the sources explain why a suggested approach may be hard to use? |
If a central theme depends on one weak paper, search further or narrow the claim. If several sources repeat the same point without adding a new population, method or finding, you may not need them all in the final discussion. Our study matrix guide shows how to record differences and build a synthesis.
When to stop adding sources
You may be ready to draft when your key themes have relevant evidence, you have checked for conflicting or newer work, and each important claim can be supported without stretching a source beyond what it says. The review should show what is known, where findings differ and what remains uncertain. Texas A&M University’s writing guidance emphasises a body of research that is appropriate in scope, relevance, significance, credibility and currency rather than a simple source tally (Texas A&M University Writing Center, n.d.).
This is a practical drafting check, not a formal claim that all research has been found. Revisit the search if your supervisor identifies a missing perspective, if new evidence appears or if your question changes. A very large reference list can still be weak when it consists of brief descriptions with no comparison.
Systematic reviews: included studies are not the same as references
For a systematic review, do not choose a target study count first and then select papers to meet it. Define the question, eligibility criteria and search process, screen the records consistently, and report what remains. The PRISMA 2020 flow diagram records identified, excluded and included records and reasons for exclusion (PRISMA, 2020). It does not prescribe a universal number of included studies.
Also separate records found by searches, reports such as published articles, studies included in the synthesis and references cited in your dissertation. These totals can differ. A review with few eligible studies may still be useful if the question and methods are sound and the limitations are reported honestly. Follow your programme’s instructions about whether the task is a full systematic review or a smaller evidence review.
Common counting mistakes
- Using a generic “sources per 1,000 words” formula as though it were a university rule.
- Adding marginal sources only to make the reference list look longer.
- Counting a guideline, a review and the original studies it summarises as independent evidence for the same claim.
- Confusing a minimum number of appraised studies with a minimum number of total citations.
- Including papers that do not fit the stated population or question.
- Assuming that a narrow review must find many eligible studies to be valid.
For help comparing and integrating evidence once your selection is defensible, use the nursing literature review writing guide. The Chapter 2 structure guide addresses the chapter’s organisation.
Frequently asked questions
Is ten sources enough for a nursing literature review?
It may satisfy a small assignment or a specified appraisal task, but it may be insufficient for a broader dissertation chapter. The brief, question, review type and quality of analysis decide. Do not treat ten as a universal threshold.
Should I count every citation in the dissertation?
No. Check what the instruction actually counts. A chapter’s core studies, all its cited sources and the entire dissertation’s references are different totals.
Does a systematic review need a minimum number of studies?
There is no universal PRISMA minimum. The included count follows the predefined eligibility criteria and search. Your university may set a project-specific rule, so check the brief before starting.
What if I find very few relevant studies?
Check synonyms, databases, eligibility limits and related settings. If the evidence remains sparse, explain that limitation and discuss with your supervisor whether the question should be reframed. Do not fill the review with unrelated papers.
Conclusion
A good nursing literature review has enough relevant, credible sources to address its defined question and compare the evidence responsibly. The right number comes from the brief, scope, review method and available research. Record why each source is included, then devote space to analysis rather than chasing an unsupported target count.
References
- Harvard College Writing Center (n.d.) Evaluating sources. Available at: https://usingsources.fas.harvard.edu/evaluating-sources-0.
- PRISMA (2020) PRISMA 2020 flow diagram. Available at: https://www.prisma-statement.org/prisma-2020-flow-diagram.
- Swansea University (n.d.) The structure of a literature review. Available at: https://www.tap.swansea.ac.uk/academic-success/academic-skills-lab/dissertation_skills/literature_review_structure/.
- Texas A&M University Writing Center (n.d.) Literature reviews. Available at: https://writingcenter.tamu.edu/guides/resources/lit-reviews.html.
- The Open University (n.d.) Introducing research in law and beyond: Gather. Available at: https://www.open.edu/openlearn/mod/oucontent/view.php?id=64922§ion=3.4.
- University of Arizona Libraries (n.d.) Conduct a literature review. Available at: https://lib.arizona.edu/research/sources/lit-review.
