A WHO report, a Federal Reserve staff paper, an NBER working paper, an Amnesty International briefing — all of these are grey literature. They show up in almost every empirical bachelor’s or master’s thesis, and this is the area where citations most often go wrong. This post walks through what grey literature actually is, when you should use it, and how to cite it correctly in APA, Harvard, and Chicago.
What is grey literature?
Grey literature is everything published outside the commercial journal-and-book system and not passed through classical peer review. The term says nothing about quality — it only describes the publication path. Common examples:
- Reports from international organizations (WHO, OECD, IMF, UNESCO, World Bank)
- Government and agency publications (BLS, CDC, EPA, ONS, Eurostat)
- Working papers and discussion papers (NBER, IZA, CESifo, MPRA, CEPR)
- Conference presentations not published in indexed proceedings
- Dissertations and habilitations not released by a commercial publisher
- Position papers and reports from NGOs, think tanks, professional associations
- Internal reports from companies, when publicly accessible
- Preprints — overlap with grey literature, usually treated separately
What grey literature is not: journal articles with an ISSN and peer review, books with an ISBN, chapters in edited volumes. Those fall into the “white” literature bucket.
Why you need it
For many topics, grey literature is your most current — or only — access to data. Three quick examples:
- If you write about the economic situation in Argentina in 2025, you cannot avoid the IMF Country Report. A peer-reviewed article on the same period will not appear before 2027.
- If you study the effectiveness of a new vaccine recommendation, you need current numbers from the CDC or ECDC, not the last review article from 2019.
- If you write about human rights violations in Belarus, alongside news coverage the only substantial primary material is the field reports of Human Rights Watch or Amnesty.
Grey literature is not second-class — it is a different publication type with different strengths (currency, data access) and different weaknesses (no external review, institutional interests).
The biggest mistake: treating grey literature like a journal article
The mistake almost every student makes: they cite a report as if it were a peer-reviewed article. No word on where it comes from, no framing, no mention in the text of who collected the numbers. That is problematic for two reasons.
First, every organization has an interest. The OECD has a different perspective on tax policy than Oxfam. The CDC has different priorities than a pharma company. If you take a position from an NGO report, you have to make the interest visible — otherwise you are disguising a perspective as “neutral science.”
Second, there is no external review. Errors in a WHO report are not hunted down by independent reviewers the way they are for a journal article, but by the authors and their line management. That is not automatically a weakness — but it has to be read into the source.
Practical rule: frame the source at the start of the sentence. Example:
“According to a report by the World Bank (World Bank, 2024), extreme poverty in Sub-Saharan Africa fell by X %.”
Not:
“Extreme poverty in Sub-Saharan Africa fell by X % (World Bank, 2024).”
The first version immediately signals who supplied the number. That is what examiners look for with grey literature, because the source is not “filter-neutral” science.
How to cite grey literature — by style
Four rules that apply regardless of citation style:
- The organization is the author when no individual is named.
- The report or series title is italicized (like a book).
- Report, working-paper, or series numbers go in parentheses after the title.
- For online sources, the URL goes at the end — with institutional reports, no access date is needed when the version is stable and numbered.
Now the style-by-style details.
APA 7
World Bank. (2024). Poverty and shared prosperity 2024 (Report No. WBG-PSP-24). https://openknowledge.worldbank.org/…
Chetty, R., Hendren, N., & Katz, L. (2023). The effects of exposure to better neighborhoods (NBER Working Paper No. 21156). National Bureau of Economic Research. https://www.nber.org/papers/w21156
World Health Organization. (2024). Global tuberculosis report 2024. https://www.who.int/…Two APA specifics: (1) When the organization is both author and publisher, the publisher name is dropped (see the WHO example). (2) Report or working-paper numbers go in parentheses after the title.
Harvard (author-date)
World Bank (2024) Poverty and shared prosperity 2024. Washington, DC: World Bank Group. Available at: https://openknowledge.worldbank.org/… (Accessed: 4 July 2026).
OECD (2023) Education at a Glance 2023: OECD Indicators. Paris: OECD Publishing.Harvard requires an access date for online-available grey literature — different from APA. Check your department’s style guide, because Harvard implementations vary widely.
Chicago (notes and bibliography)
Footnote: World Bank, Poverty and Shared Prosperity 2024 (Washington, DC: World Bank Group, 2024), 42.
Bibliography: World Bank. Poverty and Shared Prosperity 2024. Washington, DC: World Bank Group, 2024. https://openknowledge.worldbank.org/….Chicago has a separate rule for government publications (Manual §14.192 ff.) where the issuing agency goes before the title — for a student thesis the pattern above is usually enough.
DIN 1505-2 / ISO 690
DIN and ISO 690 need no special treatment: the institution is the author, the rest looks like a book entry, extended with “Report”, “Working Paper No. XX”, or “Discussion Paper” as a document-type label after the title.
How to judge quality
Before you add a grey source to your bibliography, run five questions:
- Who publishes the report? Established governmental, international, or research institutions are usually citable. For unfamiliar think tanks or associations: who funds them?
- Who are the authors? Are individuals named? Are they affiliated with a university or research body? Anonymous reports from unknown organizations are a warning sign.
- Is there a report or working-paper number? Numbered series (NBER Working Papers, WHO Technical Report Series, IMF Country Reports) are institutionally archived and stable.
- Is there a publication date? Without a date the source is basically unusable in an academic context — you can neither judge how current the numbers are nor return to the source later.
- Are the results confirmed by independent bodies? If only one organization reports a certain figure and every other measurement diverges, that is a signal.
Two categories are tricky and should be discussed with your supervisor:
- Corporate white papers — marketing brochures dressed up as studies. Usually only citable if you explicitly frame them as a company position.
- Interest-group reports (industry associations, lobby groups, activist organizations). Citable, but the interest must be labeled in the text.
Storage and link rot
Grey literature disappears from the web more often than journal articles. Two measures help:
- Save the PDF locally the moment you cite from it, with a filename in the format
<institution>-<year>-<short-title>.pdf. That lets you produce the source in a viva, even if the institution has taken the file down. - Check the Wayback Machine (
web.archive.org). If the page is archived there, note the snapshot URL alongside the original. Some supervisors now accept Wayback URLs as backup.
For reports from international organizations, link rot is less of a concern — they run stable institutional repositories. For NGO reports, think-tank papers, and position papers, saving is mandatory.
Common pitfall: the second-hand source
A mistake Acurio regularly finds when checking bachelor’s theses: the report is cited, but the actual number is drawn from a study that the report only links to. Example:
A student cites an OECD report and takes the claim “45 % of youth without a vocational degree end up unemployed.” The OECD report in turn cites a study by the German Institute for Economic Research (DIW). The bibliography only lists the OECD report.
The clean approach is to check and cite the original study — the DIW paper — directly. If you have only read the reuse in the OECD report, turn it into an explicit secondary citation: “DIW 2022, as cited in OECD 2024.”
And if you cannot track down the original, only cite the second-hand source and label the reuse in the text. That is more elegant — and more honest — than pretending you have read the DIW paper.
In short
Grey literature is not a fringe case; in many topics it is unavoidable. Citing it well requires three things: (1) name the institution as author, (2) note the report number and publication date precisely, and (3) frame the origin in the running text instead of dropping it in like a peer-reviewed article. Combined with clean storage (save the PDF, check Wayback), you have a scientifically defensible and robust source base — even without external peer review behind it.
Acurio then checks whether your citations actually match the source, even if the source is a 200-page World Bank report. What the report really supports, and where in the document the passage sits, is what the check finds line by line.