Item-Explanatory Mokken Scale Analysis: Using Nonparametric Item Response Theory to Explore Item Attributes

Researchers frequently examine the effects of item attributes (i.e., item properties, item covariates, item formats) as part of item analysis for cognitive and affective assessments. In this study, we propose and illustrate item-explanatory Mokken Scale Analysis (MSA) as an exploratory nonparametric approach to examining item attributes based on invariance principles. We used real data and an illustrative simulation to demonstrate the approach under various conditions. Our results suggest that item-explanatory MSA provides practical and theoretical insight to support measurement research in a variety of contexts. Because of the emphasis on invariance, our approach can help researchers explore the impact of item characteristics on examinee responses and evaluate the degree to which item characteristics have a consistent interpretation for all examinees. We consider the implications of our findings for research and practice, along with directions for further investigation.