PROJECT SUMMARY/ABSTRACT Medications for opioid use disorder (MOUD; methadone, buprenorphine, naltrexone) are highly efficacious treatments for OUD; risk of fatal and nonfatal overdose is significantly reduced during their use. However, MOUDs are vastly underutilized, and MOUD adoption is particularly low in residential treatment programs (RTPs). Individuals with OUD are particularly vulnerable to overdose directly following discharge from controlled environments such as RTPs when tolerance is greatly diminished. RTPs therefore represent a novel touchpoint for initiating MOUD treatment for individuals with OUD, and additional research is urgently needed to identify key factors that support scaling-up of MOUD in these settings. Recent policy changes by the Centers for Medicare and Medicaid Services (CMS) allowed state Medicaid programs to reimburse services delivered in Institutions for Mental Disease (IMDs; “IMD waiver”), i.e., RTPs with 16 or more beds, and required RTPs ensure access to MOUD. This presents a unique opportunity to study MOUD adoption in RTPs and learn about the factors that support its uptake by a particularly vulnerable population, Medicaid beneficiaries with OUD. The overall goal of this K-99/R-00 Pathway to Independence application is to supplement the candidate’s existing skillset by providing structured, intensive training in implementation science frameworks and study design, integration and analysis of large data sets to study state policies targeting adoption of evidence-based addiction treatment, and career development activities during the K-99 phase of the award. This training will take place in an outstanding training environment, fostered by an exceptional mentoring team including Dr. Stephen Crystal (Primary Mentor) and co-mentors Drs. Shawna Hudson, Frederick Altice, and Ayse Akincigil. The candidate will work closely with her primary mentor to gain expertise in working with “big data” including national Medicaid claims to study state policy natural experiments. Drs. Altice and Hudson will provide training in implementation science frameworks and study designs including mixed methods. Dr. Akincigil will support skills development in the application of novel advanced econometric methods relevant to observational study designs. The applicant will also complete formal coursework and workshops in these subject areas and participate in career development activities. Applying these newly acquired skills, this research proposes to: characterize state strategies for scaling-up MOUD in RTPs nationally (K-99 Aim 1), define national trends in MOUD utilization trajectories during RTP episodes in early-adopter states (K99 Aim 2), describe NJ RTP provider experiences with MOUD scale-up (R00 Aim 1), identify predictors of trajectory group membership in all IMD-waivered states and test the effects of a New Jersey Medicaid RTP MOUD pay-for-performance incentive (R00 Aim 2). The proposed training and research program aligns with th...