The ideal way to obtain data for a placement validity study would be to assign students randomly to the alternative learning situations (different courses, sections, levels, etc.) so that students with a full range of academic ability are in each learning situation. However, since this is rarely feasible, a study using the chosen test, without any randomization, can still provide useful information.
For SAT and ACCUPLACER placement validity studies, information from the tests or measures that are used as predictive variables is collected prior to the student entering the course of interest. The time between the testing of the student and the entrance into the course should not be lengthy. There should also not be any instructional intervention between the predictive test or measure and the start of the course.
For example, suppose you’re looking at students who took the SAT Math Test and then took the introductory math course at your institution. In this case, we don’t recommend including students who not only did those two things but also took your remedial math course before taking the introductory (credit-bearing) math course. Including these students will not give you an accurate analysis of the validity of SAT Math Test scores to predict success in your introductory math course.