Grey literature is defined as "information produced on all levels of government, academia, 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."1 A major advantage of grey literature is that because information is not published through commercial publishing channels (e.g., journals) the information can be published faster. This is especially important with emerging issues.
Grey literature includes data from many different sources with varying levels of reliability and review. Government reports, including statistical reports from agencies such as AHRQ, the CDC, and CMS as previously described in this training, are considered grey literature. Government reports are widely considered valid and reliable sources.
Dissertations, conference proceedings, newsletters, and blogs are also considered grey literature. One would expect a dissertation, which has undergone numerous reviews before a doctoral student can graduate, to be of a higher quality than a newsletter, which has little to no peer review. However, both dissertations and newsletters are considered grey literature.
1. Third International Conference on Grey Literature in 1997 (ICGL Luxembourg definition, 1997 - Expanded in New York, 2004).
2. "Libguides: Grey Literature: What Is Grey Literature?" University of Exeter Library, https://libguides.exeter.ac.uk/c.php?g=670055&p=4756572.