[R-meta] Standard error of the weighted mean in Metafor

Loren Albert lalbert at email.arizona.edu
Thu Sep 7 00:35:06 CEST 2017

Dear all,

I am using the Metafor package (version 1.9-9) for a meta-analysis of log
response ratios following Hedges et al. 1999 (citation at bottom). With
escalc I use measure = "ROM" then I use rma to fit a fixed effect model (so
method = "FE").

Hedges et al give two different equations for the standard error of the
weighted mean, one (equation 6) useful when the number of studies is large,
and one (equation 7) useful when the sample size is smaller.

In Metafor, I think that the standard error of the weighted mean produced
from the 'rma' command is from equation 6, but I would like to verify this
and also learn whether there is some option to use equation 7 instead.
Overall I have found Metafor to be a great package with good documentation,
so I apologize if I missed something about this in the documentation (so
far I have looked at help(rma), the 'Metafor' document and Viechtbauer

Hedges, L. V., Gurevitch, J., & Curtis, P. S. (1999). The Meta-Analysis of
Response Ratios in Experimental Ecology. Ecology, 80(4), 1150–1156.

Thanks in advance!


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