Grey Literature Search
Grey literature comprises documents and data not published through conventional commercial channels—including theses, government reports, clinical trial registries, conference abstracts, organizational policy documents, and working papers. Unlike journal articles, grey literature is not indexed in MEDLINE or Scopus and often lacks peer review. However, it is crucial for systematic reviews because it may contain null or negative findings that are less likely to be published (publication bias). Systematic grey literature searching is now a standard component of evidence synthesis and is recommended by the Cochrane Collaboration, PRISMA, and other methodological guidelines.
Source record
Citations copied verbatim from the method’s source record. No claim-level verification is inferred from them.
- Rothstein, H. R., & Hopewell, S. (2009). Grey literature. In J. P. Higgins & S. Green (Eds.), Cochrane handbook for systematic reviews of interventions (Version 5.0.2, Chapter 13). The Cochrane Collaboration. · URL
- Wood, A. M., Egger, M., Gluud, L. L., Schulz, K. F., Jüni, P., Altman, D. G., & Gluud, C. (2008). Empirical evidence of bias in treatment effect estimates in controlled trials with different interventions and outcomes: meta-epidemiological study. BMJ, 336(7644), 601–605. · DOI 10.1136/bmj.39465.451748.AD
- Mahood, Q., Van Eerd, D., & Irvin, E. (2014). Searching for grey literature for systematic reviews: challenges and benefits. Research Synthesis Methods, 5(4), 353–364. · DOI 10.1002/jrsm.1106
Curated claims
Claims persisted in the evidence ledger, each with its own assessment.
This view does not invent a claim assessment when the ledger has none.
Related methods
Generated from the method graph and shown as machine-suggested relations — no evidence claim is inferred.