(15pp.) We consider the relationship between the multiple- choice and free-response sections on the Computer Science and Chemistry tests of the College Board's Advanced Placement program. Confirmatory factor analy- sis shows that the free-response sections measure the same underlying proficiency as the multiple-choice sections for the most part. However, there is also a significant, if relatively small, amount of local dependence among the free-response items that produces a small degree of multidimensionality for each test.