Spurious Latent Classes in the Mixture Rasch Model

Paper Title:
Spurious Latent Classes in the Mixture Rasch Model
Journal Link:
http://onlinelibrary.wiley.com/doi/10.1111/j.1745-3984.2011.00146.x/abstract
Abstract:
Mixture Rasch models (MRM) have been used to study a number of psychometric issues such as goodness of fit, response strategy differences, strategy shifts, and multidimensionality. Although these models offer the potential for improving understanding of the latent variables being measured, under some conditions over-extraction of latent classes may occur, potentially leading to misinterpretation of results. In this study, a MRM was applied to data from a state-wide test that was initially calibrated to conform to a 3PL model. Results suggested how latent classes could be explained, but also how these latent classes might be due to applying a MRM to 3PL data. To support this latter conjecture, a simulation study was presented to demonstrate how data generated to fit a one-class 2PL model required more than one class when fit with a MRM.
Reference:
Alexeev, N., Templin, J., & Cohen, A. (2011). Spurious latent classes in the mixture Rasch model. Journal of Educational Measurement, 3, 313-332.