An item analysis of the Conditional Reasoning Test of Aggression.

This manuscript uses item response theory (IRT) to estimate item characteristics of the Conditional Reasoning Test of Aggression (CRT-A). Using a sample size of 5,511 respondents, the present analysis provides an accurate assessment of the capability of the CRT-A to measure latent aggression. The one-parameter logistic (1PL) model, two-parameter logistic (2PL) model, and three-parameter logistic (3PL) model are compared before the item analysis. Results suggest that the 2PL model is the most appropriate dichotomous IRT model for describing the item characteristics of the CRT-A. Potential multdimensionality in the CRT-A is also examined. Results suggest that CRT-A items work as theoretically intended, with the probability of selecting an aggressive response increasing with latent trait levels. Information curves indicate that the CRT-A is best suited for use with individuals who are high on latent aggression. Exploratory analyses include an examination of polytomous IRT models and DIF comparing student and employee respondents. The results have implications for future research using the CRT-A as well as the identification of populations appropriate for measurement using this assessment tool. (c) 2015 APA, all rights reserved).