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Review
. 2007 Nov 3;335(7626):914-6.
doi: 10.1136/bmj.39343.408449.80.

Uncertainty in heterogeneity estimates in meta-analyses

John P A Ioannidis  1 , Nikolaos A Patsopoulos, Evangelos Evangelou
Affiliations
Review

Uncertainty in heterogeneity estimates in meta-analyses

John P A Ioannidis et al. BMJ. .

Abstract

John Ioannidis, Nikolaos Patsopoulos, and Evangelos Evangelou argue that, although meta-analyses often measure heterogeneity between studies, these estimates can have large uncertainty, which must be taken into account when interpreting evidence

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Conflict of interest statement

Competing interests: None declared.

Figures

None
Fig 1 Confidence intervals for estimated I2 in 1011 Cochrane meta-analyses and 50 meta-analyses of genetic risk factors. The median number of studies was 7 (interquartile range 5-11) and 20 (13-26), respectively, and the median total sample size was 1112 (512-2691) and 4660 (2823-8761), respectively. The median I2 was 21% (0-50%) and 38% (5-60%), respectively
None
Fig 2 Proportion of meta-analyses with estimated I2=0% whose upper 95% confidence interval of I2 is lower than a given value
See this image and copyright information in PMC

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