[R-meta] Redundant predictors

[Arne Janssen]

Dear Wolfgang,

I am running an rma.rv with two categorical and one continuous moderator 
plus their interactions. Analysis of the full model give a Warning 
message: In rma.mv ( ...)  : Redundant predictors dropped from the model.
Based on the model output, I guess this is caused by the absence of all 
combinations of the two categorical moderators, is that correct? If so, 
is this something to worry about?

Best wishes,
Arne