Carlijn Wibbelink
2015-Apr-20 20:05 UTC
[R] Metafor - rma.mv function - variance components
Hi all,
I have a question about metafor and the rma.mv function. I have fitted a
multivariate model (effect sizes are nested within studies) and I've found
two variances:
Variance Components:
estim sqrt nlvls fixed factor
sigma^2.1 0.0257 0.1602 72 no y
sigma^2.2 0.0694 0.2635 10 no ID
I want to test whether there is significant variantion between the effect sizes
within studies (sigma^2.1: 0.0257) and/or between studies (sigma^2.2: 0.0694).
In metaSEM you can fix for example the variance within studies (sigma^2.1) to
zero to test whether there is a significant difference in fit between the models
(and if so, then there is significant heterogeneity between the effect sizes
within studies). I was wondering if this is also possible in metafor. If I fix
sigma2 to zero, then both variances are fixed to zero. However, I want to fix
only one variance to zero.
I hope that someone can help me. Thank you in advance!
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