Research skills guide_new

What is grey literature?

The term grey literature "is usually understood to mean literature that is not formally published in sources such as books or journal articles" (Lefebvre, Manheimer, & Glanville, 2008). Grey literature may include multiple types of document produced on all levels of government and by academics, businesses and organisations  in electronic and print formats where publishing is not the primary activity of the producing body. (Greynet, 2015.)   (Murdoch University Library - What is grey literature?)

Examples of grey literature include: 

• Clinical practice guidelines not published in the journal literature
• Clinical trials (including unpublished trial data)
• Conference abstracts, posters, presentations, proceedings
• Data sets, Statistics
• Publications and reports | Government (such as white papers, working papers, internal documentation)
• Publications and reports | Non-government publications and reports (e.g. from NGOs, think tanks, research institutes)
• Standards
• Technical documentation and specifications
• Theses/dissertations

Why is grey literature important?

"A wealth of knowledge and information is produced by organisations, governments and industry ... These publications, data and other materials, known as grey literature, are an essential resource in scholarly communication, research and policy making for business, industry, professional practice and civil society. Grey literature is recognised as a key source of evidence, argument, innovation and understanding in many disciplines, including science, engineering, health, social sciences, education, the arts and humanities". (Pisa Declaration, 2014)

Including grey literature can assist to:

• Address biased reporting of research results (publication bias) and provide a more balanced view of a topic. A 2007 Cochrane systematic review (Hopewell et al 2007)) found that often results from grey literature significantly affect the outcome of a review, as they often report more negative or inconclusive data than published journal articles. Cross-referencing published studies, for example, with their grey literature counterparts (e.g. study protocols, clinical trials)
• Broaden the scope of a search by locating published literature that a standard database search may miss
• Provide a range of more diverse perspectives than mainstream publications offer
• Provide more current information on, and better coverage of, new and emergent issues

Grey literature for systematic and scoping reviews

For systematic and scoping reviews, a grey literature search may be mandatory or strongly recommended. For instance, Cochrane's MECIR standards recommend authors: "Search relevant grey literature sources such as reports, dissertations, theses, databases and databases of conference abstracts. Searches for studies should be as extensive as possible in order to reduce the risk of publication bias and to identify as much relevant evidence as possible." (University of British Columbia Library's - Grey literature for health sciences)

Grey literature to support public policy and practice​​​​