Grey Literature
The definitions of grey literature can be wide-ranging. The International Conference on Grey Literature (ICGL), the primary source for scholarly research disseminating the topic of grey literature, proposed this definition in 2010:
Grey literature (or gray literature) refers to information that falls outside the mainstream of published journal and monograph literature, and which is not controlled by commercial publishers. Grey literature is usually is not widely disseminated or promoted and may not be peer-reviewed. Grey literature can sometimes be more current than traditional sources, but the quality may be variable and all sources must be critically evaluated. Searching the grey literature provides comprehensiveness and may help minimize publication bias as negative result trials or null trial results are less likely to be published in journal literature but can often be found in grey literature.
Grey literature can include:
- Conference abstracts or papers
- Government or private sector research
- Clinical trials - ongoing or unpublished
- Communication with experts and researchers in the field
- Newsletters and annual reports
- Patent applications
- Drug information
- Technical reports and whitepapers
- Theses and Dissertations
- Blogs, listserv archives, tweets
- Podcasts and videos
- Images, maps, and spatial data
- Websites, repositories, digital libraries
Bonato, S. (2018). Searching the Grey Literature. Rowman & Littlefield Publishers.
Evaluating Grey Literature:
- Grey Matters: a practical tool for searching health-related grey literatureA free online resource with checklist for grey literature searching from CADTH (Canadian Agency for Drugs and Technologies in Health)
- AACODS ChecklistA useful tool for evaluating grey literature from Flinders University
Grey Literature Sources
Some grey literature sources to consider:
- Government websites
- Non profit websites
- Professional association websites
- Institutional repositories such as Adelphi University's Scholarly Works
- Preprint servers such as Medrxiv or Biorxiv
- AHRQ - Agency for Healthcare Research and quality
- ClinicalTrials.gov - U.S. and international federally and privately supported clinical trials registry and results database
- Cochrane Central Register of Controlled Trials (CENTRAL) A highly concentrated source of reports of randomized and quasi-randomized controlled trials
- Dissertations and Theses Global - Dissertation and theses database
- ERIC - Educational Resources Information Center - online library of education research and information, sponsored by the Institute of Education Sciences of the U.S. Department of Education
- Google Scholar - Search engine for scholarly literature across many disciplines and sources, including theses, books, abstracts and articles
- ISRCTN.org A clinical trial registry recognized by the WHO and ICMJE that accepts planned, ongoing or completed studies of any design. Find and view clinical studies. Search by condition, intervention, funder, demographics, etc.
- MedNar A free, medically-focused deep web search engine providing a search of authoritative public and deep web resources, returning the most relevant results to one easily navigable page. It is a US focused tool offering a Google like interface.
- OAIster Union catalog of millions of records that represent open access resources.
- OpenDOAR - Directory of academic repositories
- Open Grey - System for information on grey literature in Europe. Open access to 700,000 references to the grey literature.
- TRIP Database Clinical search engine for evidence-based medicine
- WorldCat - Collection of library catalogs
- World Health Organization (WHO) - Provides leadership on global health matters, shapes the health research agenda, sets norms and standards, articulates evidence-based policy options, provides technical support to countries and monitors and assesses health trends
- WHO International Clinical Trials Registry Platform
Common sources of grey literature in healthcare:
