Computerized adaptive testing with the generalized graded unfolding model

The use of the generalized graded unfolding model (GGUM) in computerized adaptive testing was examined. The objective was to minimize the number of items required to produce equiprecise estimates of person locations. Simulations based on real data about college student attitudes toward abortion and on data generated to fit the GGUM were used. It was found that as few as 7 or 8 items were needed to produce accurate and precise person estimates using an expected a posteriori procedure. The number of items in the item bank (20, 40, or 60 items) and their distribution on the continuum (uniform locations or item clusters in moderately extreme locations) had only small effects on the accuracy and precision of the estimates. These results suggest that adaptive testing with the GGUM is a good method for achieving estimates with an approximately uniform level of precision using a small number of items.