TitleAn examination of decision-theory adaptive testing procedures
Publication TypeBook Chapter
Year of Publication2009
AuthorsRudner, LM
CityD. J. Weiss (Ed.), Proceedings of the 2009 GMAC Conference on Computerized Adaptive Testing.

This research examined three ways to adaptively select items using decision theory: a traditional decision theory sequential testing approach (expected minimum cost), information gain (modeled after Kullback-Leibler), and a maximum discrimination approach, and then compared them all against an approach using maximum IRT Fisher information. It also examined the use of Wald’s (1947) wellknown sequential probability ratio test, SPRT, as a test termination rule in this context. The minimum cost approach was notably better than the best-case possibility for IRT. Information gain, which is based on entropy and comes from information theory, was almost identical to minimum cost. The simple approach using the item that best discriminates between the two most likely classifications also fared better than IRT, but not as well as information gain or minimum cost. Through Wald’s SPRT, large percentages of examinees can be accurately classified with very few items. With only 25 sequentially selected items, for example, approximately 90% of the simulated NAEP examinees were classified with 86% accuracy. The advantages of the decision theory model are many—the model yields accurate mastery state classifications, can use a small item pool, is simple to implement, requires little pretesting, is applicable to criterion-referenced tests, can be used in diagnostic testing, can be adapted to yield classifications on multiple skills, and should be easy to explain to non-statisticians.