Utility of the Inventory of Callous-Unemotional Traits in adolescent offenders and non-offenders: An item response theory analysis
The current study utilized Item Response Theory (IRT) analyses to examine the item functioning of the Inventory of Callous-Unemotional Traits (ICU; Frick, 2003) in the assessment of psychopathy-linked traits in adolescents. Self-report psychopathy measures, such as the ICU, have become increasingly common for use with adolescents. However, questions remain regarding their reliability and utility for accurately assessing these traits (Poythress, Dembo, Wareham, & Greenbaum, 2006). IRT analyses offer unique methods of investigating test and item functioning in regards to the underlying trait an inventory purportedly assesses. The current study examined and compared the item functioning of the ICU for the assessment of psychopathy-linked characteristics, particularly callous-unemotional (CU) traits, in a sample of adolescent offenders as well as a non-offending adolescent sample. Based on the current results, ICU items 11, 15, 16, and 23 were the most discriminating items in the non-offender sample. Items 5, 15, 17, and 23 were the most discriminating in the offender sample. Items 11 and 17 were found to be the most difficult and discriminating items for the non-offender and offender samples, respectively. The results of the current study further indicated that eight of the ICU items functioned differently between the two samples in either discriminating ability or item difficulty. These results support the notion that differential item functioning exists between the current sample of adolescent offenders and non-offenders. Overall, the ICU appears to estimate CU traits more reliably in this sample of non-offenders compared to the adolescent offender sample.