The use of the MacCAT-CA with adolescents: an item response theory investigation of age-related measurement bias.

Despite the application of the MacCAT-CA to juveniles, questions been raised regarding the appropriateness of this tool for adolescents. The current study tested for age-related measurement bias using data from the MacArthur Juvenile Adjudicative Competence Study (n = 1393). Five of the MacCAT-CA items showed age-related measurement bias (i.e., DIF) for adolescents aged 11-15, and three items showed DIF for adolescents aged 16-17. Several items (e.g., understanding of juries) were more difficult for adolescents than adults matched at the same latent level of capacity, suggesting that these items might underestimate adolescents' legal capacities. Contrary to expectations, there was little evidence of age-related measurement bias on the Appreciation scale. The use of the MacCAT-CA in research and clinical settings is discussed.