PROJECT SUMMARY: Pilot Grant & Training Core The need for investigators who can conduct health economic studies related to substance use disorder and HCV and HIV treatment of people who use substances is growing, but a limited number have the appropriate training and skills to conduct this research. In this context, pilot research studies are particularly valuable. Pilot studies can ensure that research is responsive to the rapidly changing health policy landscape and can initiate economic data collection in a timely fashion, including alongside randomized trials or other interventional studies. These benefits are particularly critical for early stage investigators. In 2015, we established CHERISH (Center for Health Economics of Treatment Interventions for Substance Use Disorder, HCV, and HIV), a National Center of Excellence for health economic research related to substance use disorder policy and HCV and HIV care of people who use substances. The CHERISH Pilot Grant & Training Core draws on the Center’s scientific strengths, including an extensive network of expertise and experience conducting economic evaluations of substance use disorder treatment and HCV and HIV treatment of people who use substances through our investigators and growing network of Research Affiliates nationally. The Pilot Grant & Training Core’s specific aims are 1) to administer competitive pilot research awards that support the development and application of methods and dissemination tools in substance use disorder, HCV, and HIV health economic research, and 2) to conduct training activities and mentor trainees and early-stage researchers in economic evaluation methods related to substance use disorder, HCV, and HIV. We will provide pilot grant opportunities that will enable researchers to investigate innovative methodologies or applications, collect preliminary data to inform external grant proposals, and collaborate with researchers who have complementary expertise. We will continue to provide in-person introductory training sessions that are recorded and archived on our website as a virtual library of trainings. We will expand our trainings to include advanced economic evaluation trainings for more experienced researchers, to be held in conjunction with major conferences and meetings. We will initiate a new mentorship program for early-stage researchers and develop and execute a plan to engage diverse trainees and mentees. We will continue to work closely with the other Cores to achieve these aims by drawing on their expertise to review pilot grant applications, mentor pilot grantees, develop and implement training programs, and identify career mentors. These activities will result in new investigator-initiated research awards and career development awards, and a new cohort of investigators with the skills needed to conduct economic research that will have an impact on substance use disorder, HCV, and HIV health outcomes and treatment policy.