Grey literature in nursing reviews includes relevant reports and other material produced outside conventional commercial journal publishing. Examples can include organisational reports, theses, conference material and some working papers. The important question is whether a document meets your review’s eligibility criteria, not whether its format looks academic.
A careful search can identify evidence that a journal-only strategy misses. However, adding a few website links at the end does not create a systematic grey-literature search. You need a reason for selecting sources, a record of what you searched and a consistent approach to screening and appraisal.
This guide focuses on finding and documenting grey literature. For database syntax and a complete search process, use the separate nursing systematic-review search strategy guide. For selecting a review design, consult the secondary research design guide.
Decide what grey literature your nursing review needs
Start with the research question and inclusion criteria. A review of intervention effects needs eligible evaluations. By contrast, a review of policy implementation might legitimately include organisational reports or documentary material. A guidance document may explain the policy context without being an included primary study.
Cochrane’s searching guidance supports identifying relevant evidence beyond standard journal searches to reduce the effects of incomplete reporting (Cochrane, n.d.-a). The practical implication is to plan supplementary sources deliberately. It does not mean every student review must search every possible repository.
First, write an explicit rule for document types. For example, will you include a thesis reporting an eligible empirical study? Will conference abstracts be considered if a full report cannot be obtained? What minimum information is needed to assess methods and extract findings? Resolve these questions before selecting documents based on appealing conclusions.
Also, check the assessment brief. If it requires peer-reviewed primary studies only, you may use some grey literature for background while keeping it outside the included-study set. Explain that boundary. Do not silently change a university requirement because a useful report appears during searching.
Where to search for grey literature in nursing reviews
| Source type | Potential value | Main check |
|---|---|---|
| University repositories | Theses and institutional research outputs | Whether a later journal report describes the same study |
| Government and public-health bodies | Evaluations, surveillance and policy reports | Methods, population and document version |
| Health-service organisations | Service evaluations and implementation reports | Local context, independence and extractable evidence |
| Professional and voluntary organisations | Workforce, patient-experience and practice reports | Sampling, sponsorship and selective reporting |
| Trial registers | Study identification and registration information | Distinction between registration and results |
| Conference collections | Emerging or incompletely published studies | Limited detail and later full publications |
This is a source map, not a claim that every category is necessary for every review. Choose sources aligned with the population, setting and evidence type. A narrowly defined inpatient intervention question needs a different supplementary search from a review of community-service experiences.
Use the official current repository or organisation website and record the route you used. Search interfaces and coverage can change. If a suggested source is unavailable, document the limitation and choose a justified alternative rather than claiming that the unavailable resource was searched.
Qualitative evidence searching may particularly benefit from attention to theses and reports, as discussed in Cochrane’s qualitative-evidence guidance (Cochrane, n.d.-b). Nevertheless, relevance still depends on the question. Keep the search broad enough to locate meaningful accounts while retaining explicit criteria for the people, setting and phenomenon under investigation.
Build a focused source plan
Create a short list of organisations or repositories likely to hold the evidence. For each, write a one-sentence justification. “Produces national nursing workforce reports” is more informative than “well-known website”. Prioritise relevance and coverage over the number of sources listed.
Group sources by their role. Some may identify unpublished studies, while others provide contextual statistics or policy documents. Keeping these roles visible helps prevent a background report from entering an intervention synthesis without meeting the same eligibility requirements as other included evidence.
For a fictional review of discharge education, the plan might include university repositories for theses, relevant public-health bodies for evaluations and trial registers for studies without a readily located publication. This example illustrates planning and does not report a search that has already been completed.
Agree a feasible scope with the supervisor or information specialist. Student projects have resource limits, but limits should be described as limits. Avoid labels such as “all grey literature” when only a small set of English-language organisational websites was examined.
Adapt search terms to website interfaces
A database strategy may not work unchanged on an organisation’s website. Some interfaces support Boolean operators, while others respond better to short concept searches. Test the interface and record what it actually accepts. Do not present unsupported database syntax as if it ran successfully.
Break a complex question into a few distinctive concepts. Try the intervention term and population, then useful synonyms where necessary. Therefore, keep a record of each executed search. If the site supports document-type or date filters, note the selections and consider whether the filters could hide eligible material.
A general web search can supplement targeted sources, especially where a website’s internal search is weak. Record the search engine, exact query, date and the number or range of results screened. Search results can vary, so transparency matters even when perfect reproducibility is impossible.
Where you use a site-restricted query, explain the selected domain and why it is relevant. Do not treat a search engine as a substitute for every repository simply because it is convenient. A search strategy should show how the chosen routes complement one another.
Document grey literature in nursing reviews
PRISMA-S provides a framework for reporting literature searches transparently (Rethlefsen et al., 2021). For grey literature, useful details include the source, interface, date, executed terms, limits and screening process. Describe what happened rather than copying a generic search-methods paragraph.
| Log field | What to record |
|---|---|
| Source and URL | Organisation or repository and the exact search location |
| Date | When the search was actually run |
| Query | The precise terms accepted by that interface |
| Limits | Date, language, document type or other filters |
| Extent screened | Results inspected and the planned stopping approach |
| Potentially eligible records | Saved records and their identifiers |
| Notes | Access problems, changed versions or linked publications |
Use a consistent naming convention for downloaded files. Record the authoring body, year, title and version in the reference manager. If a report has an update date that differs from its original publication date, retain both details in your notes and cite the version you used.
Keep search records separate from final inclusion decisions. A document can be found in several places but only included once as a report, and several reports may belong to one study. Preserving those distinctions makes the review easier to audit.
Set a defensible stopping rule
Website searches can expand indefinitely. Before searching, decide how the search will end for each source. The rule might involve screening all results from a targeted repository query or a predefined number of search-engine results, with a reason linked to feasibility.
A numerical limit is not automatically comprehensive. If relevant records are still appearing at the stopping point, consider whether the planned scope needs revision. Record and justify any change. Do not extend searching selectively because you hope to find support for a preferred conclusion.
For broad web searches, consider how results are ordered. Relevance-ranked results and date-ranked results may produce different sets. Record the order where available. If the engine does not expose stable totals, describe the actual screening extent rather than inventing an exact total.
Finally, state limitations clearly in the dissertation. A restricted search may still be useful, but the reader should understand what could have been missed. Transparency about search limits is more credible than claiming exhaustive coverage without a record that supports it.
Screen grey literature using the same eligibility logic
Apply the population, setting, design and outcome criteria consistently. An organisational report should not receive an easier route into the review because it supports your argument. Conversely, an eligible thesis should not be rejected solely because it is not a journal article when the protocol allows theses.
Check whether the document contains original empirical work, a summary of other evidence or an opinion. A report may contain several components. Extract only the part relevant to your review and label its evidence type accurately. Avoid counting a literature summary as an additional independent study.
At full text, record a clear reason for exclusion when required by your review method. Use reasons such as ineligible population or no eligible outcome rather than vague judgements such as “not useful”. Keep the reason linked to the protocol.
If important information is missing, follow the planned approach to obtaining clarification or handling incomplete reports. Do not infer a sample size or analysis method from a press release. Missing methodological detail should influence appraisal and the confidence placed in the finding.
Appraise methods, provenance and conflicts of interest
Grey literature varies substantially in purpose and methodological detail. An official logo establishes provenance, not freedom from error. Examine who commissioned the work, who collected the data, how participants were selected and how conclusions were reached.
Choose an appraisal approach appropriate to the document and study design. A randomised evaluation, qualitative interview study and policy document raise different questions. The critical-appraisal guide explains why one checklist should not be used indiscriminately.
For a workforce survey report, consider sampling, response rate, question wording and the difference between respondents and the target population. In a service evaluation, examine baseline information, comparison conditions, measurement consistency and context. For a qualitative report, ask how accounts were generated and interpreted.
Record sponsorship and potential interests without assuming that funding alone proves invalidity. Explain how the issue affects interpretation. A report may contain valuable data while making stronger policy recommendations than the methods justify. Separate the usable findings from the author’s advocacy.
Avoid double counting studies and report versions
One study may appear as a conference abstract, thesis, organisational report and journal paper. Treating those as four independent studies exaggerates the evidence base. Compare authors, dates, setting, sample descriptions, recruitment periods and intervention details to identify linked reports.
Consequently, assign a study identifier and connect every related report to it. Decide which report provides the most complete information for each field. A later paper may contain the main outcomes while a thesis explains methods in greater depth. Record any discrepancies instead of silently choosing the most favourable number.
In addition, version control matters. A revised organisational report can replace earlier estimates. Keep the version used for extraction, note the update and explain how duplicates or superseded versions were handled. Do not delete records so completely that the audit trail disappears.
Use a nursing evidence table to make these relationships visible. Include separate fields for study identity and report details where needed. That distinction supports accurate synthesis and helps readers understand why the number of reports differs from the number of studies.
Worked example: a grey-literature search decision
Suppose a fictional nursing review asks how adults experience discharge medicine explanations. The protocol permits qualitative empirical studies, including theses and organisational research reports. A charity report containing interviews may be potentially eligible; a campaign page summarising its recommendations is background material.
The reviewer records the website search, saves the full report and checks the participants, interview methods and analysis. They then discover a journal article with the same setting and sample. Both reports are linked under one study identifier, and the richer methods account informs appraisal.
If the report combines patients and carers but does not separate their findings, the reviewer checks whether that matches the eligibility criteria. They do not invent patient-only themes. Depending on the protocol, the report may be included with a limitation or excluded with a documented reason.
This example shows why grey-literature searching involves more than locating documents. Search, eligibility, appraisal and report linkage work together. Each step protects the review from treating visibility, organisational authority or repeated publication as evidence of stronger findings.
Write the methods and limitations precisely
In the methods chapter, name the supplementary sources and explain their selection. Provide the executed searches in an appendix where appropriate. State how documents were saved, screened and linked to studies, and identify any differences from the database-screening process.
In the results, distinguish records found, reports assessed and studies included. Use the reporting framework appropriate to the review design. Do not create PRISMA counts from memory after completing the writing; reconcile them with your actual records.
In the discussion, explain how the included grey literature changes or qualifies the evidence. Did it add a different population, reveal implementation barriers or provide only weakly documented findings? Avoid treating inclusion itself as an improvement in quality.
Finally, check references for authoring body, year, report title, version and a stable link where available. Cite the report you actually read. If a webpage points to a downloadable report, make clear which item supplied the evidence.
Frequently asked questions
Is grey literature the same as low-quality evidence?
No. Publication route and methodological quality are separate questions. Appraise the design, conduct and reporting of each eligible document.
Can I include guidelines as primary studies?
A guideline usually synthesises evidence and recommendations rather than reporting one primary study. Its role depends on the review question and eligibility criteria. Label it accurately.
Must every nursing review include grey literature?
No single rule covers all assignments. Follow the review methodology, protocol and university requirements, and justify the scope of searching.
Can a web search replace database searching?
Usually it serves a different supplementary role. Explain what each route contributes and avoid presenting a small web search as comprehensive coverage.
What if a report has no named individual author?
The responsible organisation may be the author. Verify the document’s provenance and use the referencing convention required by your university.
Should I include both a thesis and its journal paper?
They may both inform extraction, but they should be linked as reports of one study where that is what they represent. Avoid counting the same participants twice.
Before you finalise the search
Check that every source has a purpose, every search has a record and every included document meets the criteria. For project-specific planning, systematic-review support can help you identify gaps in your documented process without inventing searches or evidence.
Review the gaps in your supplementary search
If you are unsure whether your source plan is defensible, bring the research question, eligibility criteria and actual search log for feedback. A useful review identifies sources that could fill a specific gap and explains how to document the work. It should never invent searches, screening totals or reports that were not retrieved.
Request feedback on your nursing review search or read how review guidance is organised. You can also examine our support principles and client reviews. For other stages of the project, visit the nursing dissertation support overview.
References
- Cochrane (n.d.-a) Chapter 4: Searching for and selecting studies. Available at: Cochrane Handbook, Chapter 4 (Accessed: 16 October 2026).
- Cochrane (n.d.-b) Chapter 21: Qualitative evidence. Available at: Cochrane Handbook, Chapter 21 (Accessed: 16 October 2026).
- Rethlefsen, M.L., Kirtley, S., Waffenschmidt, S., Ayala, A.P., Moher, D., Page, M.J. and Koffel, J.B. (2021) ‘PRISMA-S: an extension to the PRISMA Statement for Reporting Literature Searches in Systematic Reviews’, Systematic Reviews, 10, article 39. Available at: https://doi.org/10.1186/s13643-020-01542-z (Accessed: 16 October 2026).
