A modified test for small-study effects in meta-analyses of controlled trials with binary endpoints

Harbord, Roger M; Egger, Matthias; Sterne, Jonathan A C (2006). A modified test for small-study effects in meta-analyses of controlled trials with binary endpoints. Statistics in medicine, 25(20), 3443-57.. Hoboken, N.J.: Wiley-Blackwell 10.1002/sim.2380

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Publication bias and related bias in meta-analysis is often examined by visually checking for asymmetry in funnel plots of treatment effect against its standard error. Formal statistical tests of funnel plot asymmetry have been proposed, but when applied to binary outcome data these can give false-positive rates that are higher than the nominal level in some situations (large treatment effects, or few events per trial, or all trials of similar sizes). We develop a modified linear regression test for funnel plot asymmetry based on the efficient score and its variance, Fisher's information. The performance of this test is compared to the other proposed tests in simulation analyses based on the characteristics of published controlled trials. When there is little or no between-trial heterogeneity, this modified test has a false-positive rate close to the nominal level while maintaining similar power to the original linear regression test ('Egger' test). When the degree of between-trial heterogeneity is large, none of the tests that have been proposed has uniformly good properties.

Item Type:

Journal Article (Original Article)


04 Faculty of Medicine > Pre-clinic Human Medicine > Institute of Social and Preventive Medicine (ISPM)

UniBE Contributor:

Egger, Matthias and Sterne, Jonathan










Factscience Import

Date Deposited:

04 Oct 2013 14:48

Last Modified:

06 Dec 2013 13:43

Publisher DOI:


PubMed ID:


Web of Science ID:



https://boris.unibe.ch/id/eprint/20081 (FactScience: 3199)

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