The present study uses data from the US-based Nonshared Environment in Adolescent Development study (NEAD; Neiderhiser, Reiss, & Hetherington, 2007; Reiss et al., 2000), and the Swedish-based Twin and Offspring Study in Sweden (TOSS; Neiderhiser & Lichtenstein, 2008). All procedures and assessments were approved by the Institutional Review Boards (IRB) of collaborating institutions. Twins are parents in TOSS, and NEAD is a sample of adolescent twins and siblings. TOSS was designed in part to be the mirror image of NEAD, including administration of identical measures of parenting and matched adolescent ages. Previous reports have found the US and Swedish samples to be comparable on a number of key demographic and substantive variables including parental knowledge and externalizing behavior (Neiderhiser, Reiss, Lichtenstein, et al., 2007; Neiderhiser et al., 2004). These two studies have been used together in an ECOT model previously (Marceau et al., 2013).
