Dimensionality, hierarchical structure, age generalizability, and criterion validity of the GAIN's Behavioral Complexity Scale.

This study used Rasch measurement model criteria and traditional psychometric strategies to examine key psychometric properties of the Behavioral Complexity Scale (BCS), a widely used measure of externalizing disorders that focuses on attention deficit, hyperactivity, and conduct disorders. With a sample of 7,435 persons being screened for substance use disorders, the BCS was found to (a) be unidimensional, (b) have a hierarchical severity structure, (c) be generalizable to both youths and adults, and (d) meet hypothesized correlations with criterion variables. The BCS performed well as a unidimensional measure. The Rasch severity hierarchy of attention deficit to hyperactivity to conduct disorders provided a perspective that suggested that a dimensional measure could be used as an alternative and, in some ways, as an improvement to categorical diagnosis and common dimensional approaches. The finding of 3 low-severity conduct disorder items also supported a revision of categorical criteria, especially in substance use disorders.