[R-meta] Weight argument in rma.uni models

[Tina Dudenhöffer]

Dear all,

I am working with the rma.uni function to fit a multivariate random effects model.

I see that the W argument is an optional argument to specify a user-defined weight matrix. I was curious if any weight is applied if I don’t specify this argument. 
Specifically, I am wondering if the inverse variance weight is applied “automatically”, considering I am specifying the V argument in the model itself.

In terms of my model, I am wondering about the difference between these:

res5 <- rma.mv(EffectSize_NEW, Variance_New, method="REML",random = list(~ 1 | EffectSize_ID_NEW, ~ 1 | Study), data=Data)
res5

res6 <- rma.mv(EffectSize_NEW, Variance_New, W=weight, method="REML",random = list(~ 1 | EffectSize_ID_NEW, ~ 1 | Study), data=Data)
res6

Note: the argument weight in my dataset is simply: 1/Variance_New

Hope this is all clear.

Many thanks and kind regards,
Tina