[R-meta] pooled vs separate QB statistics

[Viechtbauer, Wolfgang (NP)]

Hi Filippo,

That is correct.

Best,
Wolfgang

> -----Original Message-----
> From: R-sig-meta-analysis <r-sig-meta-analysis-bounces using r-project.org> On Behalf
> Of Filippo Gambarota via R-sig-meta-analysis
> Sent: Tuesday, May 28, 2024 12:39
> To: Michael Dewey <lists using dewey.myzen.co.uk>
> Cc: Filippo Gambarota <filippo.gambarota using gmail.com>; R Special Interest Group
> for Meta-Analysis <r-sig-meta-analysis using r-project.org>
> Subject: Re: [R-meta] pooled vs separate QB statistics
>
> Dear Michael,
> Thank you. So basically when different tau2 are estimated (either
> using a multivariate model or scale location model) the Q test for the
> moderators is the non-pooled test? When a single tau2 is estimated the
> Q test is the pooled version?
> Filippo
>
> On Tue, 28 May 2024 at 12:31, Michael Dewey <lists using dewey.myzen.co.uk> wrote:
> >
> > Dear Filippo
> >
> > Does
> > https://www.metafor-project.org/doku.php/tips:different_tau2_across_subgroups
> > help?
> >
> > Michael
> >
> > On 28/05/2024 11:09, Filippo Gambarota via R-sig-meta-analysis wrote:
> > > 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., López-López, J. A., Viechtbauer, W.,
> > > Marín-Martínez, F., Botella, J., & Sánchez-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., Sánchez-Meca, J., López-López, J. A., Botella, J.,
> > > & Marín-Martínez, 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