Grey literature is the term used to describe publications that are unpublished, or which haven't been published commercially.
Grey literature is used in research because:
Go to our Systematic Review guide for information on using Grey Literature for Systematic Reviews
Search engines such as Google are also useful when searching for grey literature. Note that:
When you perform a Google search you can also limit to particular domains or by file type. Most of the grey literature available on the Web is in the form of PDF documents. Also consider restricting your search to the .org and/or .gov domains.
e.g. vaccination rural Australia file type:pdf or vaccination rural Australia site:org
Grey literature needs to be critically evaluated and appraised to determine the quality of the information. This is particularly important as grey literature has not usually received the same quality checking as peer reviewed published material. However it may still be reliable information for your research.
The AACODS checklist is a useful tool for evaluating grey literature: