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

TitleGRADE guidelines: 5. Rating the quality of evidence--publication bias.
Publication TypeJournal Article
Year of Publication2011
AuthorsGuyatt 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, Sch├╝nemann HJ
JournalJournal of clinical epidemiology
Volume64
Issue12
Pagination1277-82
Date Published2011 Dec
ISSN1878-5921
KeywordsCross-Sectional Studies; Drug Industry; Evidence-Based Medicine; Meta-Analysis as Topic; Practice Guidelines as Topic; Publication Bias; Randomized Controlled Trials as Topic; Review Literature as Topic; Statistics as Topic
Abstract

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.

DOI10.1016/j.jclinepi.2011.01.011
Alternate JournalJ Clin Epidemiol