What is it?
Grey Literature is material that has not been published in the traditional way e.g. conventional books and journals. It can include any resource that falls outside of this definition including; government publications, theses, conference proceedings, technical reports, publications from professional bodies and organisations, websites, social media and more!
Why use it?
Grey literature can cover recent or specialist topics as well as technical information which may not be well represented in academic research journals. It can include unpublished trials and data, along with other commercial or sensitive information not available in the public domain. Researchers may need to include this hard to find information to counter publication bias (publication of only favourable results).
It is important that researchers, try to the best of their ability to access as much information about their research topic, not just what has been published.
This checklist (by Jess Tyndall, Medical Librarian at Flinders University) is designed to help with the evaluation and critical appraisal of grey literature.