PROJECT SUMMARY Although up to 80% of mental health services for youth are currently provided in schools, few students receive evidence-based practices (EBPs). Even when organizational supports are in place, implementation ultimately rests with providers' motivation for change. Individual provider behavior change is critical to achieve high-quality implementation and positive outcomes for youth. For the public to benefit from the decades of research invested in EBP development, implementation strategies that target provider motivation are needed. Beliefs and Attitudes for Successful Implementation in Schools (BASIS) is a four-hour, facilitated, group- based, blended implementation strategy designed to augment standard EBP training and consultation procedures by improving provider engagement and motivation. Using strategic education, motivational interviewing, and social influence strategies, BASIS aims to impact key, theoretically-derived, individual-level mechanisms associated with clinician behavior change—attitudes, social norms, and perceived behavioral control—to improve treatment quality (i.e., fidelity), and youth outcomes. In two previous trials, BASIS delivered in-person demonstrated evidence of feasibility, appropriateness, and efficacy, but it could be optimized for greater scalability and efficiency, so that it can be used widely to positively impact clinicians' engagement. Consistent with the goals of the IMPACT Center, the current project will focus on increasing BASIS scalability by (1) optimizing BASIS to include only the most essential components for activating its target mechanisms and (2) adapting its delivery to a web-enabled digital platform. We will build causal pathways using theory and stakeholder input (practice community, youth), enroll representative end users, and use rapid analogue methods (RAM) to efficiently identify and test BASIS components, as well as prioritize them for digital deployment. Aims of this study are to apply IMPACT Center methods in order to: (1) Identify and prioritize BASIS components via causal pathway diagramming; (2) Conduct tests of prioritized BASIS components using RAM to inform the development of an optimized eHealth adaptation of BASIS (eBASIS); and (3) Test the impact of eBASIS on EBP fidelity and youth outcomes in a randomized controlled trial (RCT). Key organizational factors (e.g., leadership, implementation climate, school characteristics) will be measured as covariates during the RCT. Promising findings would support an R01 application for a confirmatory trial evaluating the impact of eBASIS on fidelity and youth outcomes. We anticipate that the eBASIS implementation strategy will be readily scalable and could enhance the impact of EBP integration efforts to improve treatment quality and outcomes for youth in the education sector and other low-resource community settings.