[R-meta] comparison between escalc("SMCR") and escalc("SMD")

Filippo Gambarota ||||ppo@g@mb@rot@ @end|ng |rom gm@||@com
Thu Jan 5 13:38:12 CET 2023

I have a very simple question about the comparison between scale ("SMCR")
and escalc("SMD"). Carefully reading Morris and De Shon (2002) the
comparison between two effect size is meaningful when the denominator
represents the same quantity. Assuming that I have a two-group comparison
and pre-post comparison on the same meta-analysis I could compute the
standard SMD for the first case and the pre-post difference divided by the
pooled sd (ignoring the correlation) in the second case. But this is not
what "SMCR" is doing because it uses the first "sd1i" which is the "pre"
standard deviation.
Is that correct? Should I compute the pooled sd before and then supplying
it as "sd1i"?

*Filippo Gambarota*
PhD Student - University of Padova
Department of Developmental and Social Psychology
Website: filippogambarota.xyz
Research Groups: Colab <http://colab.psy.unipd.it/>   Psicostat

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