[R-meta] Question about rma(measure = "COR", ..)
@c @end|ng |rom |mb|@un|-|re|burg@de
Tue Oct 22 10:37:11 CEST 2019
Am 21.10.19 um 15:22 schrieb Jalynskij, Maria:
> b) Or should I use rma(measure="ZCOR", ri = corr, ni = n, data = data), and conduct the main result back by myown at the end?
> In the second version the Trim and Fill method doesn't make any sense.
While one may question whether Trim and Fill is the best method to
adjust for small study effects in meta-analysis, I do not understand why
the method should make sense for untransformed correlations but not for
Fisher z-transformed correlations.
Trim and Fill removes the most extreme studies (trim step), determines a
symmetry axis and adds the extreme studies on the opposite side (fill
step). This works both for untransformed and Fisher transformed
Best wishes, Guido
P.S. I would always prefer to meta-analyse Fisher transformed
correlations as the meta-analysis of untransformed correlations could
result in impossible confidence limits outside -1 and 1. Accordingly,
the Fisher method is the default in /metacor()/ of R package *meta*
(which automatically does the back-calculation for the user).
Dr. Guido Schwarzer
Institute of Medical Biometry and Statistics,
Faculty of Medicine and Medical Center - University of Freiburg
Postal address: Stefan-Meier-Str. 26, D-79104 Freiburg
Mail: sc using imbi.uni-freiburg.de
ORCID iD: https://orcid.org/0000-0001-6214-9087
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