[R-meta] Meta-analysis with R, use treatment effect as input instead of 2 groups?

Guido Schwarzer sc at imbi.uni-freiburg.de
Tue Oct 17 20:18:49 CEST 2017

Am 17.10.17 um 17:57 schrieb Felix M:
> Dear All,
> I’m fairly new to R and would like to meta-analyze data where I only have
> available the differences between the outcomes for the experimental groups
> and the control groups, as well as the SEMs and SDs of those delta values.

I assume that you have the following information for each study:
delta = mean difference between experimental and control group
SEM = standard error of delta
SD = standard deviation of delta

In order to conduct a meta-analysis you only need delta and SEM.

You can use, for example, metagen() in R package meta in the following way:
metagen(delta, SEM)

Similarly, you can use rma() in R package metafor:
rma(yi = delta, sei = SEM)

See the corresponding help pages for more information, e.g. help(metagen).

Best wishes,

Dr. Guido Schwarzer (sc at imbi.uni-freiburg.de)
Institute for Medical Biometry and Statistics
Stefan-Meier-Str. 26, D-79104 Freiburg | Phone: +49 (0)761 203 6668
http://www.imbi.uni-freiburg.de        | Fax:   +49 (0)761 203 6680

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