[R] Metafor - rma.mv function - variance components
wibbeltjec at hotmail.com
Mon Apr 20 22:05:11 CEST 2015
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:
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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