PROJECT 2 SUMMARY One-third of children and adolescents experience a mental health disorder in their lifetime. Although a number of evidence-based practices (EBPs) have been developed that could address mental health disorders in children and adolescents, they are not commonly available in community settings. To increase the availability of EBPs, implementation efforts have often focused on clinician training. However, research consistently demon- strates that low-resource community settings need additional supports beyond clinician-focused efforts, to im- plement EBPs with fidelity. The Washington State EBP Initiative (“the Initiative”), an IMPACT partner, provides clinician training for community mental health centers in Cognitive Behavioral Therapy (CBT) for four common youth mental health conditions: anxiety, posttraumatic stress, behavioral difficulties, and depression. We propose to partner with the Initiative to optimize Implementation Coaching, an intervention developed and piloted by the PI to support community mental health centers in tailoring recommended implementation strategies for their organization. The goal of Coaching is to generate a positive implementation climate for CBT, leading to high- fidelity CBT delivery and positive outcomes for youth. Defined as the degree to which an innovation (CBT) is expected, supported, and rewarded, implementation climate is an important theoretical mechanism for high- quality implementation. Coaching supports CMHCs through working with CMHC supervisors who are frontline leaders in their organizations. We will first collaborate with CMHC supervisors experienced in CBT implementa- tion to optimize Coaching using Ideation, an IMPACT Challenge III method. Coaching requires optimization be- fore testing: (1) to ensure the best fit for low-resource CMHCs and 2) to be led by peer, CBT-experienced CMHC supervisors (Aim 1). Using a Train-the Trainer approach, we train and support a subset of the 10 collaborating CMHC supervisors from Aim 1 to lead Coaching. We then test the optimized Coaching intervention in a pilot RCT involving 20 CMHCs participating in the Initiative (20 supervisors, at least 60 of their clinicians), examining impact on CBT fidelity and clinical outcomes for youth (Aim 2). We compare standard Initiative implementation supports (10 CMHCs) to these standard supports plus Coaching (10 CMHCs). We use routinely entered, de- identified data to assess CBT fidelity and clinical outcomes. In the Coaching condition, peer CBT-experienced CMHC supervisors will lead Coaching with small groups of supervisors. Coaches will use an IMPACT Challenge II toolkit, co-designed with practice partners to inform their Coaching activities. Expected outcomes include an optimized Coaching strategy that could be integrated into the Initiative's standard implementation support and disseminated to the broader practice community nationally. Study aims also provide opportunities to refine IM- PACT methods and toolk...