The effect of item use over long time in computerized adaptive testing in case of CASEC

Abstract

The effect of item exposure rate on changes in item properties and the quality of proficiency estimation is one of the most important concerns for practitioners of computerized adaptive testing. This article investigates the effects of high item exposure rate and repeated item presentations to the same examinee on item properties and proficiency estimation. In this study, I focused on the Computerized Assessment System for English Communication (CASEC), which is a commercially available computerized adaptive test. Simulated as well as the real data were analyzed and compared in terms of percentage of items answered correctly, item exposure frequency, and proficiency estimates of examinees. The results suggest that the effects of item exposure on item pollution and proficiency estimation were not so serious in the case of CASEC.