Asymmetric item characteristic curve in item response theory: model construction and application

Abstract

Most of the models used in the Item Response Theory assume point-symmetry of the Item Characteristic Curve. Although the convenience of such models is obvious a priori assumption of symmetry does not always correspond to an experimental data. In many cases we deal with obviously skewed distribution and the usage of symmetric models involves inevitable errors both in experimental studies and in test constructing. The applicability of the asymmetric model for the analysis of test items is discussed in the present study. Data obtained from Raven's Advanced Progressive Matrices (N=365) are used to illustrate the analysis.