[R-meta] Meta-analysis per level or meta-regression

Hi Catia,

I don't know of research that has looked at differences between these
approaches empirically.

I would interpret the issue in terms of a difference between two
meta-regression models: one in which the between-study heterogeneity is
constrained to be equal across levels of the moderator and one in which the
between-study heterogeneity is allowed to differ by level of the moderator.
Mar?a Rubio-Aparicio and colleagues compared these two models in a
simulation study:
https://doi.org/10.1080/00220973.2018.1561404

It's also now possible to fit and compare both models using metafor:
res_hom <- rma(yi, vi, mods = ~ alloc, data=dat)
res_het <- rma(yi, vi, mods = ~ alloc, scale = ~ alloc, data=dat)
anova(res_het, res_hom) # Likelihood ratio test and model fit statistics

Some analysts would simply fit both models and justify
their preferred model based on the fit statistics. Others might argue that
it's preferable to always use the more flexible model for purposes of
testing moderators; see Rodriguez et al. (2023;
https://doi.org/10.1111/bmsp.12299).

James

On Mon, Mar 20, 2023 at 1:04?PM Catia Oliveira via R-sig-meta-analysis <

[R-meta] Meta-analysis per level or meta-regression

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