[R-meta] Q-Statistic for Between-Subgroup Heterogeneity

[Viechtbauer, Wolfgang (SP)]

Dear Ty,

The test for 'between-group' differences/heterogeneity is provided if you include the subgroup variable as a categorial moderator (i.e., as a factor) in the model. For example:

library(metafor)

dat <- get(data(dat.bcg))
dat <- escalc(measure="RR", ai=tpos, bi=tneg, ci=cpos, di=cneg, data=dat.bcg)

res <- rma(yi, vi, mods = ~ factor(alloc), data=dat)
res

In the output, you will find:

Test of Moderators (coefficients 2:3):
QM(df = 2) = 1.7675, p-val = 0.4132

This is the test for between-subgroup heterogeneity.

Best,
Wolfgang

-----Original Message-----
From: R-sig-meta-analysis [mailto:r-sig-meta-analysis-bounces using r-project.org] On Behalf Of Ty Beal
Sent: Friday, 13 July, 2018 15:46
To: r-sig-meta-analysis using r-project.org
Subject: [R-meta] Q-Statistic for Between-Subgroup Heterogeneity

I am conducting a meta-analysis of proportions using the metafor package and want to compare heterogeneity between subgroups. I don’t see an option to generate a Q-statistic for between-subgroup heterogeneity. Is there any way to accomplish this with the metafor package?

I can do this with the meta package using metaprop() and the byvar option—however, it does not let me specify separate weightings as rma() from the metafor package does.

Thanks,

Ty Beal, PhD
Technical Specialist
Knowledge Leadership

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