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 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Grey literature usually has not been peer reviewed, but may still be good, reliable information which can make it invaluable for your research.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.

A short video explaining grey literature from Western Universities library

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

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 traditional literature may miss information vital to research, especially in health sciences fields.
• It may be the best source of information on policies and programs.
• Using grey literature may help minimise publication bias in systematic reviews.
• Grey literature may include raw data and data sets.