I am conducting a multi-level meta-analysis using
rma.mv in the metafor package in R. The effect size measure I am working with is the raw mean (
measure="MN" in metafor). The sampling variance (
vi) for each datum is calculated as
I would like to test for publication bias using something akin to Egger's linear regression method, but I am not sure which predictor variable to use, given my effect size measure. I am aware of several predictor variable options (e.g.,
sqrt(vi), etc.). However, I'd like my choice of predictor to be appropriate for my ES measure and defensible (to reviewers).