I've conducted a Meta-Regression Analysis for my Masters Thesis. However, my supervisor told me that I should check if the proposed moderating variables highly correlate.
So I thought, that I can assess multicollinearity with the use of the Variance Inflation Factor. There are numerous examples on how to calculate VIF for "normal" Regression Analyses.
This requires the specification of a linear model (see this video as an example https://www.youtube.com/watch?v=pZsOn6wnGSo). However, in Meta-Regression I do not have a dependent variable. It's more that the effect size between the dependent and independent variable is the dependent variable for the meta-regression.
So my question is, how do I correctly calculate the VIF when dealing with Meta-Regression? I did not find any examples out there.
I would especially appreciate if someone could tell me what R-Packages I could use to calculate the VIF (and what I have to consider in order to do it correctly) or how I can calculate it with SPSS.
I hope that my question is clear. Thanks for considering my request.