What’s the minimum number of students needed for a placement validity study?

An AP placement validity study requires a minimum of 15 students whose AP scores and course-taking records indicate that they entered the higher-level course with AP credit. It also requires a minimum of 15 students without AP credit whose course-taking records indicate that they entered the higher-level course by completing the required introductory AP-equivalent course(s) at your institution.

A CLEP placement study requires a minimum of 15 students whose CLEP scores and course-taking records indicate that they entered the higher-level course with CLEP credit, and a minimum of 15 students without CLEP credit whose course-taking records indicate that they entered the higher-level course by completing the required introductory CLEP-equivalent course(s) at your institution.

For SAT and ACCUPLACER placement studies, course data for at least 30 students are required for a course placement analysis involving a single predictor measure. If one to three predictors are used, a minimum of 30 students is required; for four predictors, a minimum of 40 students; and for five predictors, a minimum of 50 students.