A comparison was made between four different scoring procedures for the 45-item Reading Comprehension subtest, Level I, of the Comprehensive Test of Basic Skills, Form S, for a sample of 1,000 third grade students. These students were selected to have been among those who omitted from 3 to 22 of the 45 items. Another representative sample of 1,300 students was used to obtain one and two parameter estimates of the test items. The four scoring procedures included two procedures based on the Rasch (one-parameter) model and two procedures based on a two-parameter model. For each of these, one procedure was based on all 45 items, whereas the other procedure was based on only those items which the student had attempted. In general, the students received higher ability estimates when scored on only the items they had attempted, rather than on all items. (CTM)