Performance Modeling That Integrates Latent Trait and Class Theory

Abstract
The qualitative characterization of individual performance that is central to modem psychological theory is not adequately modeled by traditional psychometric theory that assumes, among other things, unidimensionality. In the present study, data are presented that are more adequately modeled by HYBRID, a model that incorporates both latent trait and latent class components. The latent classes were defined by a cognitive analysis of the understanding that individuals have for a circumscribed domain. In addition to providing a better statistical fit, the analysis also improves the amount of diagnostic information available for a given individual.