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Grey Literature: What is grey literature


​Grey literature is "Information produced on all levels of government, academics, business and industry in electronic and print formats not controlled by commercial publishing i.e. where publishing is not the primary activity of the producing body."

CGL Luxembourg definition, 1997-expanded in New York, 2004

Grey literature is published informally or non-commercially, or remains unpublished. It can appear in many forms, including government reports, statistics, patents, conference papers and even non-written resources such as posters and infographics.

Grey literature usually has not been peer reviewed, but may still be good, reliable information. It can thus be invaluable for your research. It is produced from a variety of sources, and is usually not indexed or organised, often making it difficult to locate.

What is grey literature?

A short video explaining grey literature from Western Universities library

Examples of grey literature

Conference Proceedings Newsletters
Technical Reports Theses and dissertations
Government documents Research Reports
Patents Maps
Clinical trials and practice guidelines Blogs
Videos Census data
Informal communications pre and post print articles
White papers Working papers

For a comprehensive listing of grey literature types view the table.

Common grey literature producers


Why use grey literature?

Grey literature is used in research because:

  • It will often be more current than traditionally published sources, with a better coverage of emergent research areas. 
  • A literature search that accesses only “black literature” will likely miss information vital to research, especially in health sciences fields.
  • It can be a better source of information on policies and programs.
  • Using grey literature may help minimise publication bias in systematic reviews.
  • Grey literature is often a good source of raw data and data sets to which you wouldn’t otherwise have access.