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Recommendations for examining and interpreting funnel plot asymmetry in meta-analyses of randomised controlled trials

BMJ 2011; 343 doi: https://doi.org/10.1136/bmj.d4002 (Published 22 July 2011) Cite this as: BMJ 2011;343:d4002

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Interpreting funnel plots: does the example clarify the problem?

In educational articles aimed at very specialised statistical
issues, the choice of a clear example is a crucial point to help readers
understand the main message conveyed by the paper.

In the article by Sterne et al. [1], understanding Figure 2 is
essential, but it is unclear why three subgroups of studies (subgroups 1,
2 and 3) are proposed to interpret the results of the meta-analysis taken
as an example, whereas one could think that two subgroups are enough
(subgroups 1 and 2 pooled together vs. subgroup 3).

References

1. Sterne JAC, Sutton AJ, Ioannidis JPA, et al. Recommendations for
examining and interpreting funnel plot asymmetry in meta-analyses of
randomised controlled trials. BMJ 2011; 343:d4002

Competing interests: No competing interests

23 July 2011
Andrea Messori
coordinator
Lab. of Pharmacoeconomics, c/o Area Vasta Centro Toscana, 50100 Firenze, ITALY
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