[R-meta] Help with variance stabilizing transformation methods in Metafor

Viechtbauer Wolfgang (SP) wolfgang.viechtbauer at maastrichtuniversity.nl
Wed Jan 17 22:28:48 CET 2018

Just divide the person times by 100 before the analysis. See:


Then the forest plot will automatically show you rates per 100 pt yrs.


-----Original Message-----
From: R-sig-meta-analysis [mailto:r-sig-meta-analysis-bounces at r-project.org] On Behalf Of Todor Krastev
Sent: Wednesday, 17 January, 2018 21:34
To: Guido Schwarzer
Cc: r-sig-meta-analysis at r-project.org
Subject: Re: [R-meta] Help with variance stabilizing transformation methods in Metafor

Dear Guido,

Thank you for your prompt reply! 

It took me some time to fix it and react to your email, but I did manage in the end to fit the Poisson-normal model as described in Stijnen (2010), which led to much more logical effect estimates in my meta-analysis.
I didnt quite succeed to work it out with the Meta package due to some errors in the GLMM function and changed the decimal places manually (x100) in Metafor to obtain the numbers as %.
As you can see in the attachment, I also obtained the 0.73 value with Poisson (see attachment).

Also, maybe Wolfgang knows an simpler way to transform Forest plot values in Metafor also to achieve numbers per 100 pt yrs?

I also checked out the Meta package and does look super neat in the way it presents the individual study estimates in grey colour (makes the 95%CI visible in large studies) and also automatically gives you the weighing of studies and the measure of heterogeneity (all these I had to add manually). It definitely got my attention and I shall try it out for my next project.

Thank you once again for your great help!



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