A Generalized Partial Credit Model

Abstract

A generalized partial credit model (GPCM) was formulated by Muraki (1992) based on Masters’ (1982, this volume) partial credit model (PCM) by relaxing the assumption of uniform discriminating power of test items. However, the difference between these models is not only the parameterization of item characteristics but also the basic assumption about the latent variable. An item response model is viewed here as a member of a family of latent variable models which also includes the linear or nonlinear factor analysis model, the latent class model, and the latent profile model (Bartholomew, 1987).