Derivation and applicability of asymptotic results for multiple-subtest person-fit statistics

In high-stakes testing, it is important to verify the validity of individual test scores. Although a test, in general, results in valid test scores for most test takers, there may be individual test takers with unusual answer patterns for whom test score validity is questionable. One example of such aberrance is a test taker who guesses on a large number of questions or one who has preknowledge of the answers to some questions. An effective statistical technique (developed for a single test) was extended for tests that consist of multiple subtests, as does the Law School Admission Test. The results of simulation studies indicated that this extension was useful in categorizing test score patterns as normal or aberrant, even when subtests have only 10 items.