[R-meta] How to interpret the result of metabias function of the R package meta?

[Gerta Ruecker]

Dear Safa,

First, the last line of your code should probably read

metabias(MA, method="linreg",k.min=7)

The reason why the test does not indicate significant asymmetry is 
probably that there are only 7 studies. Recommendations say that one 
should test for funnel plot asymmetry only if there are at least 10 
studies (Sterne JAC et al. , Recommendations for examining and 
interpreting funnel plot asymmetry in meta-analyses of randomised 
controlled trials, BMJ 343, July 22 2011).

Best,
Gerta

Am 02.03.2021 um 16:00 schrieb Safa Aouinti:
> Dear All
>
>
> I am learning how to make a meta analysis of binary outcome data. So I chose the Fleiss93 dataset available in the meta package. This is my code:
>
> library(meta)
> data(Fleiss93)
> MA <- metabin(event.e, n.e, event.c, n.c, data=Fleiss93, studlab=paste(study, year), method = "Inverse",sm="OR")
> forest(MA)
> funnel(MA, studlab = TRUE)
> metabias(res, method="linreg",k.min=7)
>
> The funnel plot looks like asymmetric but when I use the function metabias to test this asymmetry I found a p-value=0.399 > 5% indicating that the hypothesis H0 should be accepted 'the funnel plot is symmetric' ???
>
> For me the result is contradictory to what I expect. I misinterpreted the result or I did not choose the correct method to put in metabias function ??
>
> Thank you in advance for your help/ explanations !
>
> Best regards.
>
> Safa Aouinti
> Ph.D. in applied Mathematics and Statistics
>
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-- 

Dr. rer. nat. Gerta Rücker, Dipl.-Math.

Institute of Medical Biometry and Statistics,
Faculty of Medicine and Medical Center - University of Freiburg

Stefan-Meier-Str. 26, D-79104 Freiburg, Germany

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