"Grey literature stands for manifold document types produced on all levels of government, academia, business and industry in print and electronic formats that are protected by intellectual property rights, of sufficient quality to be collected and preserved by libraries and institutional repositories, but not controlled by commercial publishers, i.e.where publishing is not the primary activity of the producing body.” (International Conference on Grey Literature, 2010).
It is sometimes referred to as ephemeral, fringe, gray or fugitive literature.
Not peer-reviewed
Lacks editorial polish
Not conventionally published
Raw data
Incomplete work
Unorganised research
Less prestigious
May be made publically available or distributed privately
Different bodies produce grey literature, including the University and you. It is produced by the medical sciences, business and social sciences, all levels of government and industry in print and electronic formats. Here are some additional examples:
Looking for unpublished material is a good way to counteract publication bias and include a broader scope of the literature. However, grey literature has not been through any peer review process and needs to be carefully evaluated. Flinders University have created the AACOD checklist to enable evaluation and critical appraisal of grey literature:
A Authority
A Accuracy
C Coverage
O Objectivity
D Date
S Significance
Not all grey literature will have a named author (or authors). If it does, consider whether the author or authors are knowledgeable in the field and whether they have any affiliations that might bias their views. If no authors are named, consider closely the source that produced the report. Source information should be obvious and easy to locate. It should be clear where data and other types of information came from, how it was analysed and how the final report was compiled; transparency of method. The date a report was issued should be easy to find. If a report is older, try to find a more recent version or an update; currency.
Benefits of including grey literature in the review process include:
It can be tricky to find grey literature because traditionally there were no central sources such as libraries or databases where it would be collected. It is not systematically described, organised or indexed. Neither has it gone through a formal peer-reviewing process and it has been argued that for this reason grey literature should not be included in systematic reviews.
It can be harder and more time-consuming to identify relevance in the title and abstract stage of a review as citation information or abstracts may not exist and it does not conform to a specified format (abstract, methods, results, discussion) as peer-reviewed literature does.
Examples of where to search for grey literature:
Google Scholar advanced search – academic material
Google advanced search - general search
