Grey Literature

The term grey literature is used to describe a wide range of different information that is produced outside of traditional publishing and distribution channels, and which is often not well represented in indexing databases.

A widely accepted definition in the scholarly community for grey literature is

"information produced on all levels of government, academia, business and industry in electronic and print formats not controlled by commercial publishing" ie. where publishing is not the primary activity of the producing body." 

From: Third International Conference on Grey Literature in 1997 (ICGL Luxembourg definition, 1997  - Expanded in New York, 2004).

Uniqueness and currency v quality and longevity

Grey Literature can be a very important research resource.

• It can record findings in niche or emerging research areas and also record research findings that produce null or negative results.  These may not be addressed by the commercial publishers - who may have a more mainstream, profit based publishing strategy.
• It may be more current than formally published research literature which can take time to pass through a sometimes lengthy peer review and editorial publishing process.
• It can connect you with content from a more diverse range of authors and institutions.  Not everyone is able to publish through commercial publication routes

You should be aware of the need to assess and capture potentially useful resources

• Grey Literature sources can vary hugely in terms of quality.
• Scholarly publications such as books and journals pass through a formal publishing process and are subject to in depth editing review. In many cases there is a peer review process where draft versions are subject to a scrutiny process by a panel of experts.  Papers may be modified and improved in light of the expert feedback before reaching final published status. 
• Not all grey literature material is subject to a similarly rigorous pre publication review process, so you should exercise caution and make your own assessment for quality, reliability and potential bias.  See the Evaluating Sources tutorial for more guidance on this.
• Grey literature is often not formally published. For example, a report may be posted to a government website or a poster presentation may be given at a conference. In these cases you need to consider the longevity of the resource.  Something may be available on the web, or a blog for a short period only and may not be formally archived. 
• Make sure you keep a record of material you wish to use/reference - as it may not be there for discovery later down the line.

A wide, and growing, range of material can be considered as grey literature. Not all these examples will be relevant to all researchers.   For example, clinical trial information is primarily of interest to health and medical research.  Business researchers will find company and market research information particularly useful.

You should consider which types of information you are interested in before you begin searching as this will help you target and frame your online searching.

Examples include:

• Blogs
• Clinical trials
• Company Information
• Conference papers/proceedings
• Datasets
• Discussion Forums
• Dissertations and theses
• Email discussion lists
• Government documents and reports
• Interviews
• Market reports
• Newsletters
• Pamphlets
• Patents
• Policy statements
• Pre print articles
• Press releases
• Research reports
• Statistical Reports
• Survey results
• Tweets
• Wikis
• Working papers

If you prefer an audiovisual introduction, take a look at this short video, produced by the University of Guelph Library.