Validation of a Cognitive Diagnostic Model: Analysis Across Multiple Forms of a Reading Comprehension Assessment

This research sought to fit a diagnostic classification model across multiple forms of a passage-based reading comprehension assessment using the attribute hierarchy method. Previous research on diagnostic classification models for reading comprehension assessments served as the basis for selection of the final set of attributes included in the hierarchy. The two different attribute hierarchies were compared to determine the best fit. Each model was fit to the data obtained from three forms of a large-scale operational assessment for high school students. One model consisted of nine attributes and the other model consisted of eleven attributes. Model-data fit for the two models was evaluated to determine if a single model of reading comprehension could be applied to multiple operational testing forms.