Checking for collinearity in stratified models?

[SAS93]

I'm building two race-specific models using complex survey data. As a part of this process, I want to check for collinearity, which I haven't done outside of the classroom, which was a couple years ago.

Anyway, when I check for collinearity, I planned to use the regular PROC REG procedure. Do I also include the stratification variable, or since it is being stratified/controlled for anyway, can I exclude it?:

Proc REG data=fluvx;
Model flu = rec_shot race2 age edu fpl reg_status bpinsur dpinsur marital_stat   / VIF TOL COLLIN COLLINOINT ;
Run;

[PaigeMiller]

Since it could be that the collinearity between the variables differs by race, I would use PROC REG with a BY RACE; statement.

[SAS93]

I hadn't thought of that, but that makes sense! Thank you!

[Ksharp]

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