STEM Librarian
Importance in Systematic Reviews
It is important to include grey literature into a systematic review in order to help minimize publication bias.
Grey literature includes documents produced by the government, academics, business and industry in both print and electronic formats where publishing is not the primary activity of the organization.
Grey literature examples:
- Conference abstracts
- Presentations
- Proceedings
- Theses and dissertations
- Meeting records
- Reports (progress reports, annual reports)
- Government documents
- Newsletters and bulletins
- Standards and patents
- Toolkits, curriculums
- Lecture presentations and notes
Sources of Grey Literature
Searching the grey literature can be overwhelming. It is recommended to search sources that are related to your research question. Start with searching for Abstracts and Conferences. If the question includes drugs and interventions, check pharma data and trial registries. Further, browse papers and reports of relevant stakeholder organizations. Below are some examples of where to search for grey literature.
- Cochrane Central Register of Controlled TrialsA highly concentrated source of reports of randomized and quasi-randomized controlled trials. The majority of CENTRAL records are taken from bibliographic databases (mainly MEDLINE and Embase), but records are also derived from other published and unpublished sources.
- ClinicalTrials.govThe US registry for clinical trials. Includes new, ongoing, and completed human clinical trials both in the US and countries around the world.
- WHO Library DatabaseThe WHO library database includes governing documents, reports and technical documentation.
- MedNarMedNar searches across more than 60 medical research sources, including commercial databases, medical societies, NIH resources, and other government resources.
- Wikipedia Clinical Trial Registries ListThe Wikipedia entry contains a list of links to individual clinical trial registries by country.
- NY Academy of Medicine Grey Literature ReportProvides further information about grey literature and it includes a list of organizations and their links.
- ProQuest Dissertations and Theses Global This link opens in a new windowA comprehensive collection of dissertations and theses from around the world. Full-text coverage spans from 1743 to the present, with citation coverage dating back to 1637.