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Grey literature is published informally or non-commercially, or remains unpublished.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Grey literature usually has not been peer reviewed, but may still be good, reliable information.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.
Grey literature differs from "black literature" which is the familiar peer-reviewed publications found in commercial publishers' databases.
See the PHCRIS Introduction to Accessing the Grey Literature and the HLWiki page on grey literature for a more detailed overview. They are aimed at medical researchers but are relevant to anyone searching for grey literature.
A short video explaining grey literature from Western Universities library
|Technical Reports||Theses and dissertations|
|Government documents||Research Reports|
|Clinical trials and practice guidelines||Blogs|
|Informal communications||pre and post print articles|
|White papers||Working papers|
For a comprehensive listing of grey literature types view the greynet.org table.
Grey literature is used in research because: