Dear Sebastian,

Many researchers may transform the Pearson coefficients into Fisher's
z scores first by using
z <- 0.5*log((1+r)/(1-r)).

The standard errors of the Fisher's z scores are z.SE <- 1/sqrt(n-3)
where n are the sample sizes (see
http://en.wikipedia.org/wiki/Fisher_transformation).

Either metagen {meta} or meta.summaries {rmeta} can be used to conduct
a fixed- or a random-effects meta-analysis.

-- 
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Mike W.L. Cheung               Phone: (65) 6516-3702
Department of Psychology       Fax:   (65) 6773-1843
National University of Singapore
http://courses.nus.edu.sg/course/psycwlm/internet/
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On Fri, Feb 13, 2009 at 7:11 PM, Sebastian Stegmann <
stegmann@psych.uni-frankfurt.de> wrote:

> Dear R-Community,
>
> I'm currently trying to find a way to conduct a meta-analysis in R.
> I would like to analyze data from mostly-cross-sectional survey-studies.
> The
> effect sizes would be correlations.
>
> The R packages "meta" and "rmeta" are, as far as I can see, set up for
> analysis with effect sizes for differences (i.e. comparison of the
> means/odds-ratios of experimental and control group).
>
> Only the function "metagen" from the "meta"-package looks like it would
> work
> with correlations. The problem here: One would need to know the standard
> error of the correlation. The SE is not usually reported in the studies I
> have (only means, SDs and Alphas for the single variables). So the SE would
> have to be calculated somehow... But maybe "metagen" is the wrong function
> to start with in the first place?
>
> I'm wondering whether there might be anyone knowing how to conduct a
> meta-analysis based on correlations in R?
>
> Thanks in advance
> Sebastian
>
> P.S.: Of course, I'm dreaming of such a step-by-step-script like the
> absolutely marvellous ones provided by Bliese for multilevel-analysis in R
> :-)
>
> ---------
> Dipl.-Psych. Sebastian Stegmann
> Managing Editor, British Journal of Management
> Goethe University
> Institute of Psychology
> Department of Social Psychology
> Kettenhofweg 128
> 60054 Frankfurt am Main
> Germany
> http://www.sozialpsychologie.uni-Frankfurt.de/
> Phone: +49 (0) 69 / 798-23078
> Fax:   +49 (0) 69 / 798-22384
>
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