[R-meta] pooled vs separate QB statistics

[Yefeng Yang]

Dear  Filippo,

"Pooled" means you add the categorical variable as a "predictor"  or "independent variable" to the model.
"Non-pooled" means you conduct separate analysis for each level of the categorical variable.

Best regards,
Yefeng
________________________________
From: R-sig-meta-analysis <r-sig-meta-analysis-bounces using r-project.org> on behalf of Filippo Gambarota via R-sig-meta-analysis <r-sig-meta-analysis using r-project.org>
Sent: 28 May 2024 20:09
To: R meta <r-sig-meta-analysis using r-project.org>
Cc: Filippo Gambarota <filippo.gambarota using gmail.com>
Subject: [R-meta] pooled vs separate QB statistics

Hi,
I was reading the two papers (at the end) about categorical moderators
and the omnibus test and despite the conclusion is that the Q (or F)
test based on the pooled tau2 estimation works better in most cases,
when k in each moderator level is large and tau2 is expected to differ
across levels, it is better to use the non-pooled method.

Reading the metafor documentation it is not clear to me how to
implement the non-pooled method. Maybe I am missing something but I
can change the type of test (z vs t vs knha that takes into account
tau2 uncertainty) but I see no option to choose the pooled vs non
pooled tau2 method.

Thanks
Filippo

Rubio-Aparicio, M., L�pez-L�pez, J. A., Viechtbauer, W.,
Mar�n-Mart�nez, F., Botella, J., & S�nchez-Meca, J. (2020). Testing
Categorical Moderators in Mixed-Effects Meta-analysis in the Presence
of Heteroscedasticity. Journal of Experimental Education, 88(2),
288�310. https://doi.org/10.1080/00220973.2018.1561404

Rubio-Aparicio, M., S�nchez-Meca, J., L�pez-L�pez, J. A., Botella, J.,
& Mar�n-Mart�nez, F. (2017). Analysis of categorical moderators in
mixed-effects meta-analysis: Consequences of using pooled versus
separate estimates of the residual between-studies variances. The
British Journal of Mathematical and Statistical Psychology, 70(3),
439�456. https://doi.org/10.1111/bmsp.12092

--
Filippo Gambarota, PhD
Postdoctoral Researcher - University of Padova
Department of Developmental and Social Psychology
Website: filippogambarota.xyz
Research Groups: Colab   Psicostat

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