- Find Information
- Research Guides
- Basics of Systematic Reviews
Basics of Systematic Reviews
Step 3b: Searching Grey Literature
In order to perform a comprehensive search of the available literature, you should also search grey literature. Grey literature is research and other types of information produced outside of academic or traditional publishing channels like scientific journals. Examples of grey literature include:
| Completed clinical trials | Research studies that test a medical, surgical, or behavioral intervention in people. |
| Conference Proceedings | (can include posters & papers) |
| Government Reports | International, national, and local governmental documents. |
| Preprints | A full draft of a research paper that is shared publicly before it has been peer reviewed. |
| Statistical Data | Often considered grey literature as they are published by government, research organizations and researchers, not by traditional publishing sources. |
| White Papers | A research-based report that examines a topic and offers potential solutions to a problem. |
| Guidelines and Position Papers | Issued by organizations (such as American Cancer Society) produced outside of traditional publishing and distribution channels. |
There are a number of places you can search for grey literature, including:
- MetaLibA federated search engine that searches multiple U.S. Federal government databases. Useful for searching for government reports
- National Science Foundation Public Access RepositoryThis public access repository may be useful in locating conference papers and datasets.
- Data.govUseful for searching open datasets.
- Google ScholarGoogle Scholar is useful in finding a wide variety of grey literature. Contact your librarian for search tips on how to effectively locate grey literature using this resource.
- OSF PreprintsOSF offers a feature to search preprints by subject area, creator, institution, and other criteria.
- DiscoverGovA federated database aggregating many government databases into a single, searchable database.
Step 3c: Applying PRISMA
There are guidelines available for suggested reporting items when documenting your search in the written portion of your review. For this step, review the PRISMA-S checklist, which is the search reporting extension of PRISMA. Make sure to specify the dates when each resource was last searched. It's important to document the full search strategy used in each database, register, or website. Any applied limiters and filters should be documented as well and included in an appendix.
- PRISMA-S for SearchingContains a checklist for reporting databases searched, registers, websites, reference lists, and other sources consulted to identify relevant literature.