[R] Metafor vs Meta vs Spreadsheet: wrong numbers

Viechtbauer Wolfgang (STAT) wolfgang.viechtbauer at maastrichtuniversity.nl
Thu Jan 13 23:30:15 CET 2011

Dear Serge-Étienne,


res <- rma.uni(yi, vi, data=dat, method="DL")

for the random-effects model when using the metafor package. You used method="HE" -- this will give you a different estimator of tau^2 then the one used in the meta package.


Wolfgang Viechtbauer
Department of Psychiatry and Neuropsychology
School for Mental Health and Neuroscience
Maastricht University, P.O. Box 616
6200 MD Maastricht, The Netherlands
Tel: +31 (43) 368-5248
Fax: +31 (43) 368-8689
Web: http://www.wvbauer.com

----Original Message----
From: r-help-bounces at r-project.org
[mailto:r-help-bounces at r-project.org] On Behalf Of Serge-Étienne Parent
Sent: Wednesday, January 12, 2011 18:18 To: r-help at r-project.org
Subject: [R] Metafor vs Meta vs Spreadsheet: wrong numbers

> Hello,
> I experimented the Metafor and Meta packages in the scope of
> replacing  Excel for meta-analysis. I performed the first working
> example provided  in Michael Borenstein's book "Introduction to
> Meta-Analysis" with Excel,  Metafor and Meta. The numbers given by my
> spreadsheet, which I  validated from Borenstein's book, conrespond
> quite closely to those  given by Meta, but are different from those
> obtained using Metafor. For  the fixed effect, I infer that the
> differences are related to numerical  issues, but for the random
> effect, the numbers are considerably  different. Unfortunately, I
> could not find where I made it wrong. I  would be grateful if someone
> would have a look at my calculations.
> Here are the meta-analysis commands:
> library(metafor)
> ( dat<-escalc(m1i=m1i, sd1i=sd1i, n1i=n1i, m2i=m2i, sd2i=sd2i,
>   n2i=n2i, measure="SMD", data=metaData, append=T) ) # COMPUTE EFFECT
> SIZE ( res<-rma.uni(yi,vi,data=dat,method="HE", level=95) ) ###
> RANDOM EFFECT ( res<-rma.uni(yi,vi,data=dat,method="FE", level=95) )
> ( res<-metacont(metaData[,3], metaData[,1], metaData[,2],
>   metaData[,6], metaData[,4], metaData[,5],
>     studlab=rownames(metaData),sm="SMD", level = 0.95, level.comb =
>     0.95, comb.fixed=TRUE, comb.random=TRUE, label.e="Experimental",
> label.c="Control", bylab=rownames(metaData)) )
> The whole R script is temporarly available at http://bit.ly/eYesbZ
> The spreadsheet is temporarly available at http://bit.ly/fAYWPo
> Kind regards,
> S.-É. Parent, Eng., Ph.D.
> Department of Soils and Agrifood Engineering, Université Laval Canada

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