Combined with other studies using the ECOT design, the present findings highlight that different aspects of parenting are related to adolescent behavior for different reasons. Evocative rGE explained the association between maternal and paternal negativity with externalizing behavior in the same samples (Marceau et al., 2013), consistent with many, but not all (e.g., Klahr, McGue, Iacono, & Burt, 2011) genetically informed studies of parental negativity and externalizing problems. Thus, based on evidence from ECOT models, it may be that parents can exacerbate adolescent externalizing behaviors by responding with negativity, but diminish adolescent externalizing behaviors by gaining knowledge regarding their adolescents’ whereabouts and activities. The ECOT design has been used previously to test specific aspects of negative parenting (i.e., over-involvement and criticism, Narusyte et al., 2011; Narusyte et al., 2008). This is the first investigation of associations between a positive parenting behavior and adolescent behavior to employ the ECOT model. Continuing to apply the ECOT model to test the mechanisms underlying associations between parenting and adolescent behavior will be important for informing intervention both in terms of reducing negative behavior and in terms of promoting positive development by identifying optimal targets of intervention.