GRADE guidelines: 5. Rating the quality of evidence--publication bias.

Journal Article (Journal Article)

In the GRADE approach, randomized trials start as high-quality evidence and observational studies as low-quality evidence, but both can be rated down if a body of evidence is associated with a high risk of publication bias. Even when individual studies included in best-evidence summaries have a low risk of bias, publication bias can result in substantial overestimates of effect. Authors should suspect publication bias when available evidence comes from a number of small studies, most of which have been commercially funded. A number of approaches based on examination of the pattern of data are available to help assess publication bias. The most popular of these is the funnel plot; all, however, have substantial limitations. Publication bias is likely frequent, and caution in the face of early results, particularly with small sample size and number of events, is warranted.

Full Text

Duke Authors

Cited Authors

  • Guyatt, GH; Oxman, AD; Montori, V; Vist, G; Kunz, R; Brozek, J; Alonso-Coello, P; Djulbegovic, B; Atkins, D; Falck-Ytter, Y; Williams, JW; Meerpohl, J; Norris, SL; Akl, EA; Schünemann, HJ

Published Date

  • December 2011

Published In

Volume / Issue

  • 64 / 12

Start / End Page

  • 1277 - 1282

PubMed ID

  • 21802904

Electronic International Standard Serial Number (EISSN)

  • 1878-5921

Digital Object Identifier (DOI)

  • 10.1016/j.jclinepi.2011.01.011


  • eng

Conference Location

  • United States