Grey literature refers to research studies which are not found in traditional academic publications such as scholarly journals. This could include publications such as clinical trial protocols, dissertations, or government reports.
In addition to scholarly articles published in academic journals, you may want to also use grey literature to complete your review for reasons such as:
Much grey literature can be located on the Internet. You can begin by searching the websites of the key organisations in your research area, such as advocacy groups, government agencies, professional associations, and research institutes.
There are also databases that provide access to grey literature:
Because grey literature is not usually put through the same peer-review process or quality checks as academic articles or books, it is important to critically evaluate the quality of grey literature before including it in your review. A useful tool for evaluating grey literature is the ACCODS checklist.