PROJECT SUMMARY: METHODS CORE (C) Building off our success as a Core in the D-ARC, in this transition to a Full ARC, we will expand upon our services and training in statistical analysis techniques, research design, qualitative approaches, mental health (MH) measurement, and data management. Because of CHARM’s theme related to reducing the impact of MH and minority health disparities across the HIV prevention and care continua, we focus on multi-level methods. MH comorbidities are inherently individual-level processes. In contrast, MH and minority health disparities are driven by higher-level structural socio-cultural processes that exist at the various levels (e.g., neighborhoods, cities, regions) within which individuals are nested. Therefore, interventions and approaches of Center investigators are likely to address both individual and socio-cultural processes and, thus, be multi-level. The Methods Core is responsible for promotion of state-of-the-science research design (statistical methods and qualitative approaches) via consultation in multi-level research that will inform local implementation of evidence-based practice consistent with CHARM goals. Activities to address this aim include providing consultation to MH-HIV researchers developing grant proposals (as well as post-award support) and supporting early-stage investigators with CHARM Developmental Core Awards Program studies in the areas of research design, use of biomarkers of HIV and its comorbidities, and analytic strategies. To optimize resource-sharing and collaboration on MH-HIV research among CHARM investigators, the Methods Core will expand a unified data architecture, centralized data repository, and collaborate across cores on an instrument library. The voluntary unified data architecture includes common data elements to facilitate collaboration and cooperative projects to utilize CHARM data in ways not possible in single studies. The Core also maintains databases for both consent-to-contact databases implemented by the Mental Health Disparities and Community Engagement Core and the CHARM REDCap Measures Library of well-established validated instruments; including Spanish and Haitian Creole-language measures of constructs relevant to HIV and MH. Finally, the Methods Core provides triaged access to CHARM resources, state-of-the-science methodology workshops, and other capacity-building activities focused on addressing MH disparities in HIV. Via the CHARM Research Navigation Portal, investigators and community partners are provided coordinated access to all CHARM resources, methodology consultations, and methods-focused workshops with content on machine learning, reproducibility, multilevel modelling, geographically-focused analysis, intersectionality, reliability and validity across populations, and model selection approaches. The Core also facilitates consultations and presentations from other CHARM Cores and affiliated research groups, such as the CFAR, CTSI, NIDA’s Nat...