[R-meta] Meta-analysis with missing data

[Gabriele Midolo]

Dear Mekides,

I think this is a common issue in agricultural and ecological
meta-analyses. But I am not sure the solution to your problem depends on
metafor. However, based on my experience, there are few options to be
considered (with the following order): 1) to contact the authors of the
primary studies and ask them to provide the SD of the means; 2) to compute
the missing SD via the ‘impute_SD’ function of the R package metagear
(Lajeunesse, 2016), in case few values are missing; 3) you might consider
to perform an "unweighed meta-analysis" including also the studies without
SD to compare results with a meta-analysis including studies with available
SD only? See an example in e.g. of Humbert et al. 2016 Global Change
Biology, 22(1), 110-120. (Figure 1).

Hope this helps,
Gabriele.


Il gio 28 mar 2019, 16:06 Mekides Gardi <mekides.gardi using uni-hohenheim.de> ha
scritto:

> Dear All,
>
> Seeking help on meta-analysis. I am conducting a meta-analysis on the
> response of two cereal crops to elevated CO2. Most of the studies
> didn't report SD or SE. I have the mean values for both the control
> and experimental group and sample size as well.
> I read on literature there is still a way to do meta-analysis without
> SD or SE. Could you provide me with guides on how to do it in R with
> metafor package?
>
> Thanks in advance.
>
> Mekides
>
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