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Grey Literature in the Health Sciences: Evaluating It

Guide to locating and evaluating grey literature (or gray literature) in the health sciences.

Evaluating Grey Literature

The criteria you would use to evaluate grey literature are the same as those used to evaluate any kind of information. Consider:

  • Authorship. Not all grey literature will have a named author (or authors). If it does, you will want to 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, you will want to consider closely the source that produced the report.
  • Source of the Report. This information should be obvious and easy to locate. Check below for more information on evaluating agency and organization Web sites.
  • Transparency of Methods. It should be clear where data and other types of information came from, how it was analyzed and how the final report was compiled.
  • Currency. 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.

Evaluating Agency and Organization Web Sites

Although it is often suggested that searches for grey literature be restricted by domain, do not rely on the .org or .edu domains when evaluating Web sites. The .org domain no longer only applies to non-profits. Sites with URLs ending in .edu may also be personal student or faculty pages, rather than official university pages.

Also, don't count on the professional look of a Web page to indicate quality. Some very reputable sources of information can have Web sites that look dated. Some less reliable sources of information, on the other hand, are beautifully designed. Take a look at this site for RYT Hospital. It looks very professional until you look more closely at the content, which includes patient services such as "Head Transplantation".

If you are unfamiliar with an agency or organization, you can check to see if it is listed in reputable directories of organizations. Look it up in one of the directories of grey literature producing organizations listed here.

The AACODS Checklist, put together by Jess Tyndal at Flinders University, is a good resource for more information on evaluating grey literature.

Example of a good report

For an example of a good report, take a look at this one from Agency for Healthcare Research and Quality (AHRQ) Screening and Diagnosis of Gestational Diabetes Mellitus.

  • Authorship. Although there are no named authors, the report describes groups of Key Informants and Technical Experts consulted for the report starting on page 13. How potential conflicts of interest are handled is discussed there as well.
  • Source of the Report. The source - AHRQ - is clearly stated on each page. This is a well-respected U.S. Government agency, in the .gov domain, which is listed in many collections of grey literature producing organizations.
  • Transparency of Methods. The methods and evaluation criteria are clearly outlined starting on page 6 of the report. The search strategy used to generate literature for review is provided in an appendix to the report.
  • Currency. The date, December 16, 2011, is clearly indicated on each page of the report.

Screencapture of AHRQ logo from a report