Admission Validity Studies

What’s the minimum number of students needed for an admission validity study?
We don’t capture HSGPAs in our student information system; is this a problem?
How should we handle student course grades of Fail, Incomplete, or Withdraw?
Can we include students who don't complete their first year in our admission validity study?
Can we include students who are missing SAT scores in our admission validity study?
Can we include part-time students in our sample for an admission validity study?
How many predictors can I include in my admission validity study?
How should we choose predictors for an admission validity study?
Why would we want to request additional subgroups in an admission validity study?
The cohort we want to study has fewer than 50 students; can we do an admission validity study?
Can we include international students in our admission validity study?
How can I include special subgroup analyses in my admission validity study?