The individual components of the approach in the present study are not new. There are precedents in the literature of modeling actuarial predictions from growth curves (Deater-Deckard et al., 1998; Lussier & Davies, 2011), of modeling growth curve trajectories derived from different raters (Odgers et al., 2008) and different measures/scales (Owens & Shaw, 2003; Pettit et al., 2007) from childhood to adulthood (Curran et al., 2008), and of rendering measures more equivalent with proportional scoring metrics in the context of growth curves (McArdle et al., 2000). What is novel in the present study is the assembling of these approaches to predict risk for developing externalizing problems from childhood to adulthood. We believe this is a methodological and conceptual advance toward understanding development, because using different measures over time is necessary for describing development across long spans characterized by changes in how the same construct is manifested over time, or heterotypic continuity. Following Rutter and Sroufe’s (2000) argument that developmental psychopathology research should strive to understand development over the lifespan, we were able to chart the development of externalizing behavior over
