Detecting and Interpreting Local Item Dependence Using a Fannily of Rasch Models

This paper describes a method for detecting and in terpreting disturbances of the local independence as sumption among items that share common stimulus material or other substantive features. Dichotomous and polytomous Rasch models are used in an example to analyze Structure of the Learning Outcome (SOLO) superitems and examine the results for local independ ence problems. The results indicate that some disturb ances were present among particular subsets of the items. Index terms: local independence, partial credit model, one-parameter logistic model, Rasch model, rating scale model.