Effects of Item-Selection Criteria on Classification Testing with the Sequential Probability Ratio Test. ACT Research Report Series.

This paper presents comparisons among three item-selection criteria for the sequential probability ratio test. The criteria were compared in terms of their efficiency in selecting items, as indicated by average test length and the percentage of correct decisions. The item-selection criteria applied in this study were the Fisher information function, the Kullback-Leibler information function, and a weighted log-odds ratio. Also examined were the effects of the cutoff scores, the width of the indifference region, the item pool size, and the item exposure rate under the different item-selection criteria. Three types of selection criteria, 3 different cutting points, 11 indifference regions, 2 different item pool sizes, and 3 item exposure rates were examined. The results of the computer simulations showed that the three criteria yielded very small differences in the outcome measures, regardless of the conditions imposed. (Contains 6 tables and 10 references.) (Author/SLD)