Detecting item memorization in the CAT environment
The purpose of appropriateness/person-fit indices is to identify response patterns for which a given item response theory model is inappropriate for an examinee even though that model is appropriate for a group. This study was concerned with those cases in which examinees had prior knowledge of items from an item bank used to generate a computerized adaptive test (CAT) and used the memorized information to inflate their test scores. The objective was to evaluate procedures that could identify these individuals by examining the application of person-fit indices in the CAT environment. The lzand ECI4 zindices were selected for comparison. Using information from these indices, a new method was developed. All three indices showed little power to detect the use of memorization. Some possibilities for altering a test when the model becomes inappropriate for an examinee are also discussed.