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This new section of the Journal is aimed at providing the essential information readers should know about the topics that are addressed in the "Statistics in practice" paper published in the same issue of the journal. This stand-alone section has to be seen as an articulated summary of the main notions clinicians have to know about some basic concepts in statistics, which may be useful for their evidence based practice. After going through these notes, readers are encouraged to read the "Statistics in practice" articles. Of course, we welcome any feedback from you (via email or Twitter) about this!
The EBMH Editors
Funnel plot
A funnel plot is a scatter plot of the treatment effect estimates from individual trials against a measure of study's precision (usually the standard error (SE)). 1 Asymmetry in the funnel plot should not be automatically equated with publications bias.
There are various alternative explanations for funnel plot asymmetry, such as heterogeneity, selective outcome reporting and chance.
A sizeable number of studies (by convention, usually at least 10 though more may be needed in the presence...