In this study, data from an operational computerized adaptive test (CAT) were examined in order to gather information concerning item response times in a CAT environment. The CAT under study included multiple-choice items measuring verbal, quantitative, and analytical reasoning. The analyses included the fitting of regression models describing the relations of item parameters, ability measures, and item serial position with item-level response times. All of these analyses were performed for data collected under two different conditions: the first in which the test takers were only required to answer 80% of the items to receive a score, and the second in which the test-taker score was proportional to the number of items answered. The results for 2 datasets, 1 with 21,366 test takers and 1 with 11,301 test takers were compared. The results show that ability is predictive of item-level response times for items on the verbal section for both datasets, while item difficulty is predictive of item-level response times for certain sets of quantitative and analytical items. In each case, the regression equations explain more of the variability in the item-level response times when the data were administered under the proportional adjustment scoring rule. An appendix describes the method used and gives an example. (Contains 11 tables, 13 figures, and 29 references.) (Author/SLD)