Background: VIF-stepwise test deals with multicollinearity and automatically eliminate the highly correlated variables according to the determined threshold. The problem is when using bioclim 19 variables, there are variables derived from original variables like bio1, 2 and 12 and this affects the elimination process. Since they are the source, they are found highly correlated with the other derived variables, thus excluded first. VIF-step doesn't distinguish between original -important variables in my opinion- and other derived variables.
Now for PCA, it works on one by one collinearity with no self eliminating option so the user must choose the variables to be retained and this requires defense later -on why we choose this variable over the other-. I thought in another approach where I will use PCA along with jackknife results to determine what variables to retain. This approach will allow me to retain some original variables and I can depend on their Jackknife results in the defense.
My main questions are: is the third approach scientifically valid? and is it more robust than VIF-stepwise test?.
Side question: how can we defend the variables we chose using PCA alone?
I think the purpose should be to find correlated variables rather than eliminate them? Also, PCA is used to kind of show correlations, but I suppose by default it can show uncorrelated. But usually we ignore uncorrelated variables :)
Use both!
The following links will be useful:
- https://www.mdpi.com/2076-3417/10/3/1107/htm
- https://onlinelibrary.wiley.com/doi/10.1111/ecog.01881
@ Andrew Paul McKenzie Pegman
I think you got me wrong, my purpose is to find the highly correlated variables (>0.7) and eliminate one of each pair. To eliminate one and retain the other, here, there should be an explanation of why this variable was chosen over the other .. at least a good paper would do that. Reading some statistical papers, I think I should stick to VIF since it's more precise than PCA in terms of multicollinearity.
Hi Areej Jaradat , I just came across your post since I was searching more about VIF. I actually used select07 and hier.part to select variables (
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