Medicine: Grey Literature

Guide to information resources and services for Medicine, including basic and clinical sciences.

Grey literature

What is grey literature?

Grey literature is information which has been published informally or non-commercially, or remains unpublished. It can appear in many forms, including conference papers, government reports, statistics, patents, patient information sheets or posters.

Grey literature is not usually peer-reviewed, but may still be good, reliable information. Appraisal of grey literature should be conducted with the same rigour as with peer review.

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.

The University of South Australia has a comprehensive Grey Literature guide.

Why is grey literature important?

  • Exhaustive searching of the evidence base, such as when conducting a systematic review, requires a search of both published and unpublished sources.
  • Grey literature such as conference papers, may be a good source of new information on emerging treatments, drugs or medical interventions that have not yet been published in peer reviewed journal articles.
  • Grey literature may also report the preliminary findings of scientifically valid studies, that were not published due to negative or insignificant results.

"Published trials tend to be larger and show an overall greater treatment effect than grey trials. This has important implications for reviewers who need to ensure they identify grey trials, in order to minimise the risk of introducing bias into their review"
Hopewell et al. Grey literature in meta-analyses of randomized trials of health care interventions. Cochrane Database Sys. Rev. 2007.

"failure to identify trials reported in conference proceedings and other grey literature might affect the results of a systematic review" Grey literature databases. Cochrane Handbook for Systematic Reviews of Interventions.

Grey literature can be found  through a number of methods, including:

  • Search engines
  • Databases
  • Grey literature reports, newsletters and directories
  • Websites of relevant organisations

This guide lists some resources to help you get started, but is not comprehensive - you'll need to look elsewhere as well.

Grey literature is hard to find - be systematic!

Before you start searching, ask yourself:

  • What exactly am I looking for? Be as specific as possible.
    • What do you hope to find out from the grey literature?
    • Are there limits on what you're interested in? e.g. must be about Australia, not other countries
  • Who might produce or collect that kind of information?

This will influence how and where you search.

Tips for using search engines:

  • Use multiple search engines - they often give different results
  • Try restricting your search to .pdf or .doc files using the advanced search
    • These file types are often used to distribute reports and other documents
  • Restrict your search by domain if appropriate
    • e.g. Australian government websites end with

For more detailed guidance, see the online tutorials  Academic research on the internet and Developing a search strategy.

Evaluating grey literature
You should evaluate every source you use, but it's particularly important to do so when using grey literature.
The quality of grey literature can vary greatly as it comes from a wide range of sources and doesn't go through the traditional editorial process.

The AACODS checklist is designed to enable evaluation and critical appraisal of grey literature.
The checklist includes the following

  • Authority
  • Accuracy
  • Coverage
  • Objectivity
  • Date
  • Significance

Tyndall, J. AACODS Checklist.  Flinders University, 2010.  Available from

Evaluating sources section of the Academic research on the internet tutorial can also help guide you through an evaluation process.

Library databases that include some grey literature:

Many other databases include conference proceedings, check their descriptions on the databases library guide.


Use Search to find Monash theses, and Trove for other Australian theses. See the theses library guide for international theses and more detailed information.

Government publications:

See the library's government publications guide for more detailed advice on locating documents from Australia and other countries.

Selected Australian government sites:

Search tools, directories and newsletters:

Other websites: