There are three ways to test validity in a tool:
self-evident measures (face and content), pragmatic (criteria),
construct validity (theory basis).
What is Pragmatic (criteria)?
Concurrent validity - urine dipstick vs. urinalysis. you know the dipstick works because when you compare the results to the alysis, it's the same.
Predictive validity - measure now, and see it it's true. ATI measures ability to pass nclex. You pass ATI? you pass nclex = ATI works.