Project Summary A majority of youths referred to community mental health services shows symptoms of more than one disorder. Transdiagnostic, modular psychotherapies are designed for such youths and have proliferated in recent years, with the most thoroughly-studied being Modular Approach to Therapy for Children with Anxiety, Depression, Trauma, or Conduct Problems (MATCH). MATCH has produced better clinical outcomes than usual and standard evidence-based care in some effectiveness trials, but not others, highlighting the need to identify methods for improving its effectiveness. One such method may be to address a significant challenge of MATCH and modular therapies in general: the requirement that clinicians make numerous and frequent decisions about module selection and application throughout treatment. In MATCH, clinicians are encouraged to make these decisions based on baseline and weekly measurement-based care data from MATCH consumers—i.e., youths and caregivers. However, clinician use of these measures in decision-making is not standardized or systematic; thus, the degree to which consumer perspectives are leveraged to inform decisions is variable. Beyond the use of consumer-reported measures, clinical decisions might also benefit from information derived from collaborative interactions with consumers. Indeed, a growing body of research indicates that clinician- consumer collaboration can improve decision-making in, and the personalization and effectiveness of, youth psychotherapy. In line with the NIMH’s Research Priority 4.1 “to improve the effectiveness…of existing mental health services,” the current study aims to assess both forms of clinician-consumer collaboration: (1) measure- based—i.e., clinician use of consumer-reported measures to guide decisions, and (2) interaction-based–i.e., clinician efforts to engage one or both consumers in collaborative decision-making during MATCH sessions. This study will leverage data from a completed trial, in which 42 clinicians provided MATCH to 200 clinically- referred youths (7-15 years old). Using these data, this study will assess measure-based clinician-consumer collaboration at the start of MATCH (Aim 1), and throughout MATCH sessions (Aim 2), as predictors of treatment processes and youth clinical outcomes. To assess interaction-based collaboration, Aim 3 will involve the development, application, and evaluation of an observational coding system of clinician-consumer collaboration during audio-recorded MATCH sessions. This coding process will yield data to test (Aim 4) interaction-based clinician-consumer collaboration throughout MATCH as a predictor of the same processes and outcomes tested in Aims 1 and 2. Overall, the proposed research will provide multi-method tests of the associations between several forms of clinician-consumer collaboration across the course of care, and key processes and outcomes of MATCH. Ultimately, this work is positioned to advance our understanding of clinician-c...