[R-meta] How to compare two independent meta-analyses?
Viechtbauer, Wolfgang (SP)
wo||g@ng@v|echtb@uer @end|ng |rom m@@@tr|chtun|ver@|ty@n|
Tue Jun 22 12:33:55 CEST 2021
If there is no overlap of the studies included in the two meta-analyses, then it's quite easy. Say mu-hat = .25 (95% CI: .19 to .31) and mu-hat = .46 (95% CI: .22 to .70) for the two MAs. Then:
yi <- c(.25, .46)
sei <- c((.31 - .19) / (2*qnorm(.975)), (.70 - .22) / (2*qnorm(.975)))
rma(yi, sei=sei, mods=c(0,1), method="FE")
estimate se zval pval ci.lb ci.ub
intrcpt 0.2500 0.0306 8.1665 <.0001 0.1900 0.3100 ***
mods 0.2100 0.1262 1.6638 0.0962 -0.0374 0.4574 .
So 0.21 is the difference between the two estimates, which is not significantly different from zero (p = .096).
See also: https://www.metafor-project.org/doku.php/tips:comp_two_independent_estimates
If there is overlap of the studies, then things get more tricky since the estimates from the two meta-analyses cannot be assumed to be independent then. I vaguely recall reading an article that describes a method that takes this into consideration (without requiring additional information), but can't find it right now.
>From: R-sig-meta-analysis [mailto:r-sig-meta-analysis-bounces using r-project.org] On
>Behalf Of Patrizio E Tressoldi
>Sent: Tuesday, 22 June, 2021 11:37
>To: r-sig-meta-analysis using r-project.org
>Subject: [R-meta] How to compare two independent meta-analyses?
>is it possible to compare the results of two m-a having only the effect
>size with their 95% confidence intervals and the number of studies?
>If not, which is the recommended procedure?
>Patrizio E. Tressoldi Ph.D.
>Science of Consciousness Research Group
>Università di Padova
>Padova - ITALY
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