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Grey Literature: What is a grey literature?

This guide explains what grey literature is and how and where to find it.

What is grey literature?

Grey literature (sometimes called "fugitive" literature) is material which is not formally or commercially published.

It is produced by government departments or agencies, international agencies, local authorities, academic institutions, professional or scholarly associations, think tanks, charities, non-profit organisations, companies and other organisations.

It includes, but is not limited to, the following sorts of materials

  • reports
  • working papers
  • policy documents, guidelines
  • discussion papers, briefings
  • booklets, pamphlets, fact sheets
  • conference, symposium or workshop papers or posters
  • theses and dissertations
  • information on clinical trials
  • technical notes
  • standards

Grey literature can be hard to trace; details are not usually included in bibliographic databases (with some exceptions).  However,  the online resources detailed in this guide make it easier to locate than at any time in the past

Why search for grey literature?

Grey literature can be very useful:

  • Very recent information, or research, may not yet have been formally published in a journal article or book - but might be available in a working paper or conference paper etc.
  • In relation to health information, a search for grey literature mitigates against "publication bias". Results of studies showing the positive effects of a drug or treatment are far more likely to be published in journals than those showing no or negative effects; a search for grey literature will ensure all relevant results, whether positive or negative, are located and can be evaluated.
  • Reports from professional bodies (whose focus is on specific practice areas) may examine particular topics in more depth, or on a more practical level, than mainstream publications.

However, it is also important to remember that:

  • Grey literature is not peer reviewed so may not be of the highest quality; in contrast, the most highly regarded journals are peer reviewed (articles therein are reviewed by experts to ensure they contain accurate information and are of a very high quality prior to their publication).
  • It may not always be possible to judge accurately the appropriateness of the research methods used in unpublished briefings or reports covering scientific or health research,.
  • Grey literature can take all sorts of forms and be written in lots of different styles - so care must be taken when extracting complex data and information.
  • Papers and fact sheets from particular bodies with a financial interest in a field may not be unbiased.

Critical appraisal

Not sure if you can trust grey literature you have found?

The AACODS checklist contains questions designed to help you assess the Authoritym Accuracy, Coverage, Objectivity, Date and Significance of the material.

Systematic Reviews

If you are searching for grey literature as part of a systematic review, don't forget to view our dedicated Guide to Systematic Reviews.

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