An application of the multidimensional random coefficients multinomial logit model to evaluating cognitive models of reasoning in genetics.

This article summarizes multidimensional Rasch analyses in which several alternative models of genetics reasoning are evaluated based on item response data from secondary students who participated in a genetics reasoning curriculum. The various depictions of genetics reasoning are compared by fitting several models to the item response data and comparing data-to-model fit at the model level between hierarchically nested models. We conclude that two two-dimensional models provide a substantively better depiction of student performance than does a unidimensional model or more complex three- and four-dimensional models.