Investigating Approaches to Controlling Item Position Effects in Computerized Adaptive Tests

Abstract

Item position effect (IPE) refers to situations where an item performs differently when it is administered in different positions on a test. The majority of previous research studies have focused on investigating IPE under linear testing. There is a lack of IPE research under adaptive testing. In addition, the existence of IPE might violate Item Response Theory (IRT)’s item parameter invariance assumption, which facilitates applications of IRT in various psychometric tasks such as computerized adaptive testing (CAT). Ignoring IPE might lead to issues such as inaccurate ability estimation in CAT. This article extends research on IPE by proposing and evaluating approaches to controlling position effects under an item-level computerized adaptive test via a simulation study. The results show that adjusting IPE via a pretesting design (approach 3) or a pool design (approach 4) results in better ability estimation accuracy compared to no adjustment (baseline approach) and item-level adjustment (approach 2). Practical implications of each approach as well as future research directions are discussed as well.