PROJECT SUMMARY/ABSTRACT This application is for a competing renewal of the Center for Prevention Implementation Methodology for HIV and Drug Abuse, a NIDA P30 Center of Excellence. The number of new HIV cases in the US remains stable at 56,000 per year and continues to disproportionately affect some groups, including young men who have sex with men (YMSM), especially from racial/ethnic minorities. The purpose of this methodology center is to develop new methodologies that can be used by federal and local agencies and communities to reduce HIV incidence. Biomedical interventions and strategies, including pre-exposure prophylaxis (PrEP), rapid testing for HIV and early and consistent treatment for persons who are HIV positive (Treatment as Prevention, TasP) have been shown to have high efficacy and effectiveness in reducing HIV transmission, but there remains a giant gap between what research knows and what services needed to reduce population level incidence of HIV. The major premise of this application is that the effective biomedical to reduce HIV incidence and disparities are in hand, but success will only be achieved when they are implemented in ways that meet individual, community, and health care delivery system needs. This methods proposal addresses this major gap between research and practice through implementation science and methodology, focusing on innovative ways to address the complex, mulitilevel interactions needed to implement HIV prevention programs effectively. Two Cores, an Administrative Core and an Innovative Implementation Methods Core for HIV and Drug Abuse will carry out this work. Aim 1 is to develop innovative methods to maximize the impact of implementation research in HIV prevention. We do this through an extended set of systems science and engineering methods that focus on improving the measurement of implementation, the modeling of implementation strategies, and the testing of implementation strategies through rigorous trials. Five qualifying grants support this work. Aim 2 is to apply these innovative methods to close the gap between existing research, policy, and practice for HIV prevention. In addition to working closely with our five qualifying grants, we work locally with municipal Departments of Public Health and the federal Substance Abuse and Mental Health Services Administration (SAMHSA) HIV programs to identify and prioritize gaps in knowledge, find optimal implementation strategies for reduction of HIV transmission, and design the next large implementation trials. Aim 3 is to disseminate methods and train/mentor leaders at the intersection of HIV prevention, implementation science, and drug abuse fields to improve implementation of HIV prevention programs. This involves mentoring the early career researchers, publishing, and providing training to networks of HIV and drug abuse researchers.