This study examined the relationship of a machine-scorable, constrained free-response computer science item that required the student to debug a faulty program to two other types of items: multiple-choice and free-response requiring production of a computer program. The free-response items were from the College Board's Advanced Placement Computer Science Examination. Data were from 614 college students for whom records were complete. Confirmatory factor analysis was used to test the fit of a three-factor model to these data and to compare the fit of this model to three alternatives. These models were fit using two random-half samples, one given a faulty program containing one bug and the other a program with three bugs. A single-factor model best fit the data for the sample taking the one-bug constrained free-response, and a two-factor model fit the data for the second sample. In addition, the factor intercorrelations showed this item type to be significantly related to both the free-response items and the multiple-choice measures. An appendix gives samples of the item types. (Contains 7 tables and 21 references.) (Author/SLD)