The Dimensional Nature of Externalizing Behaviors in Adolescence: Evidence from a Direct Comparison of Categorical, Dimensional, and Hybrid Models

Researchers have recognized the importance of developing an accurate classification system for externalizing disorders, though
much of this work has been framed by a priori preferences for categorical vs. dimensional constructs. Newer statistical technologies
now allow categorical and dimensional models of psychopathology to be compared empirically. In this study, we directly compared
the fit of categorical and dimensional models of externalizing behaviors in a large and representative community sample of
adolescents at two time points separated by nearly 2.5 years (N = 2027; mean age at Time 1 = 11.09 years; 50.8% female). Delinquent and aggressive behaviors were assessed with child and
parent Child Behavior Checklist reports. Latent trait, latent class, and factor mixture models were fit to the data, and at
both time points, the latent trait model provided the best fit to the data. The item parameters were inspected and interpreted,
and it was determined that the items were differentially sensitive across all regions of the dimension. We conclude that classification
models can be based on empirical evidence rather than a priori preferences, and while current classification systems conceptualize
externalizing problems in terms of discrete groups, they can be better conceptualized as dimensions.