A difficult result to interpret in Computerized Adaptive Tests (CATs) occurs when an ability estimate initially drops and then ascends continuously until the test ends, suggesting that the true ability may be higher than implied by the final estimate. This study explains why this asymmetry occurs and shows that early mistakes by high-ability…

Model checking in item response theory (IRT) is an underdeveloped area. There is no universally accepted tool for checking IRT models. The posterior predictive model-checking method is a popular Bayesian model-checking tool because it has intuitive appeal, is simple to apply, has a strong theoretical basis, and can provide graphical or numerical…

The reliability of derived measures from 4 cognitive paradigms was studied using 19 Navy enlisted men (aged between 18 and 24 years). The paradigms were: graphemic and phonemic analysis; semantic memory retrieval; lexical decision making; and letter classification. Results indicate that derived scores may have low reliability. (SLD)