Goals of the parent project and proposed supplement: This is a request for an administrative supplement to the Guiding Good Choices for Health study (4UH3AT009838, Kuklinski/Sterling), which tests the implementation feasibility and effectiveness of embedding Guiding Good Choices (GGC), a group-based prevention program for parents of early adolescents, in three large, integrated, geographically distinct healthcare systems serving socio-economically diverse families. GGC reduced adolescent alcohol, tobacco, and cannabis use, depression, and delinquent behavior in two previous randomized controlled trials. It also strengthened parenting practices and parent-adolescent relationship quality, both broadly protective against behavioral health concerns. GGC has the capacity to achieve population-level impact on adolescent health if made widely available through pediatric primary care and can help fulfill the American Academy of Pediatrics' Bright Futures recommendation that pediatricians offer developmentally tailored anticipatory guidance to all parents to support their children's healthy development. The study team successfully recruited 1,975 adolescents empaneled with 75 pediatricians and delivered GGC to intervention arm families in the three healthcare systems. We are now conducting follow-up assessments and beginning to examine key questions guided by the RE-AIM framework (GGC Reach, Effectiveness, Adoption, Implementation, and Maintenance), including assessing the feasibility and sustainability of GGC within each healthcare system, through qualitative interviews with HCS leaders, pediatricians, and clinic staff. Administrative supplement: The COVID-19 pandemic that began in March 2020 delayed the GGC4H trial by 7 months and led to several additional time- and resource-intensive activities. We are requesting supplemental funding to answer the key questions posed from the study's outset about GGC's effectiveness and implementation feasibility when offered in pediatric primary care in a pragmatic trial. We will use the supplemental funding to achieve the following aims: Aim 1: Complete planned follow-up assessments with all adolescents, continue extraction of electronic health record data, and finish preparing adolescent data from both cohorts for analysis of GGC effectiveness and cost-effectiveness. Aim 2. Complete analyses of the feasibility and effectiveness of implementing GGC in three large integrated health care systems, using the RE-AIM framework. With supplemental funding we plan to continue implementation analyses; evaluate hypothesized reductions in the study's primary outcome of substance use initiation, secondary behavioral health problems (e.g., substance use frequency, mood symptoms and diagnoses, delinquency), and exploratory outcomes (e.g., emergency department and inpatient service utilization); and conduct cost-effectiveness analyses evaluating GGC costs in relation to value gained. Evidence of feasibility and effectiveness in thre...