[R] meta-analysis normal quantile plot metafor

[Michael Dewey]

At 15:53 11/01/2012, Ricc wrote:
>Hello,
>
>I once used the metawin software to perform a meta-analysis (see
>metawinsoft, Rosenberg et al.) and produced normal qqplot to test for
>a potential bias in the dataset.
>I now want to re-use the same dataset with the package metafor by W.
>Viechtbauer (great package btw).
>
>I run the qqnorm.rma.uni function. I use standardized effect sizes as
>in metawin.

I think it would help if you said which parameters you used to 
control the envelope. Did you smooth it? Did you use the Bonferroni correction?


>QQplot generated with metafor differs from the plot obtained with
>metawin: most of the datapoint fall outside the confidence envelope
>(using the same confidence level). I don't understand very well how
>the "pseudo confidence envelope" was created in metafor. Is it more
>conservative than that from metawin or created using the package
>envelope ? Unfortunately I do not have access to metawin's code so
>that I cannot compare implementations but the manual let me think that
>metawin print classical confidence interval...
>
>Thanks for input !
>Ricc
>
>More precisions:
>R version 2.13.1 (2011-07-08)
>Platform: x86_64-pc-linux-gnu (64-bit)
>metafor_1.6-0

Michael Dewey
info at aghmed.fsnet.co.uk
http://www.aghmed.fsnet.co.uk/home.html