[R-meta] Error Stopped because k = 0 after sub setting.
I have some problems with analysis in subgroup It showed this message: > # fit random-effects model in the three subgroups
res.s <- rma(yi, vi, subset=(interven=="PZQ"),data=dat)
Error: Stopped because k = 0 after sub setting?. How should I fix it? Is it caused from vi, yi? Best regards, Klaow