Detecting Overestimation of Discrimination Parameter Applying Mutual Information

Abstract

Local item independence is generally a strong assumption for applying item response theory. Chen and Thissen (1997) proposed two models of local item dependence. One of the two is surface local dependence (SLD) which typically affects overestimations of discrimination parameters. This study evaluates the performance of some local item dependence indices focusing on the SLD condition. Simulation study was performed and computed local dependence indices with jIRTNew (Tsai & Hsu, 2005b) 0.35. The study suggests that the local item dependence indices applying mutual information are promising for detecting SLD and overestimations of discrimination parameters.