This guide introduces you to grey literature, why you might use it in your research and how to find different types of grey literature.
On this page you can find out what is meant by grey literature and examples of different types of grey literature you may come accross. It also highlights why you might want to use grey literature in your research but also what to watch out for when using grey literature.
If you want to know how to search for and find grey literature click on Finding grey literature below or in left-hand menu.
The term 'grey literature' refers to a wide range of information which is not formally or commercially published, and which is often not well represented in library research databases.
While there are a number of definitions for grey literature, in the academic community a widely accepted definition is
information produced on all levels of government, academia, business and industry in electronic and print formats not controlled by commercial publishing i.e. where publishing is not the primary activity of the producing body.
From: Third International Conference on Grey Literature in 1997 (ICGL Luxembourgh definition, 1997 - Expanded in New York, 2004).
Grey literature is usually produced by government departments and agencies, local authorities, academic institutions, professional organisations, research groups, think tanks, charities and comes from many other sources.
Not all of these examples listed will be relevant to all researchers. The primary grey literature in the sciences may differ from grey literature in the arts and humanities. Have a think about the types of information you are interested in before you begin searching.
Examples include:
To find current and emerging research: Formally published research can take time going through lengthy peer review and editorial processes unlike materials such as trial registers, pre-prints and working papers which provide details of ongoing research. Upcoming research can also be found in conference proceedings as conferences are often where new research is first announced.
To broaden your research: Innovations from the private sector, policy from government and engagement with the public as patients or beneficiaries of research will not generally be published in academic journals and books. Policy documents, industry papers and social media will help you keep up to date with social and economic updates in your field.
To mitigate against 'publication bias': Studies showing positive research results are much more likely to be published in journals. A search for grey literature will help to ensure that all relevant results, even if negative, are located.
To find viewpoints of individuals, such as patients and consumers.
To find more in depth or practical coverage of topics: Research results may be more detailed in primary source reports and documents.
To access unpublished conference proceedings and research.
Much of the content in this guide is taken from or inspired by the University of Exeter Library's Grey Literature support guide and City, University of London Library's Grey literature guide.
