Measuring higher education outcomes with a multidimensional Rasch model.

A multidimensional Rasch model was applied to two instruments measuring abilities in two related areas of a university general education curriculum. Grades from related courses were also calibrated using the Rasch model. Thus, course grades, test items, and persons were all placed on the same metric. Incorporating grades within the metric provided additional meaning to the measures; instructors could see which items were matched to students in a particular grade range for a course. This could help not only in interpreting items but also in interpreting grades. Test items and grades fit the model reasonably well, with adequate person separation reliability.