CLINICAL AND POPULATION SCIENCES CORE (CORE D) PROJECT SUMMARY The Clinical and Population Sciences (CPS) Core is an essential resource for DC CFAR investigators, providing clinical, biostatistics and epidemiology services to support HIV research in a wide range of disciplines and across multiple institutions. The CPS Core is led by an experienced team of senior HIV investigators: Dr. Princy Kumar (GU, Director - Clinical), Dr. Sam Simmens (GW, Co-Director - Biostatistics) and Dr. Manya Magnus (GW, Co-Director - Epidemiology). The Specific Aims of the Core are: 1) to provide comprehensive clinical, biostatistics and epidemiology consultation services to DC CFAR investigators; and 2) to expand the magnitude and impact of clinical and population HIV science in Washington, DC. Since 2015, the Core leadership and CPS Core service providers have provided >360 Core services. The most frequently requested services were consultations on study design and biostatistics, reviews of grant proposals and manuscripts, data analysis, and guidance on study implementation issues such as recruitment and retention. The Core has connected investigators with scientific collaborators and community members and facilitated access to existing cohort data and biorepositories. From 2015-2019, these services supported 56 unique investigators, 58 publications, 66 pilot award applications, seven administrative supplements, 59 NIH grant submissions and 10 new NIH grants. Innovative programs such as the No Investigator Left Behind and MACC Scholars initiatives and enhanced access to cohorts and specimens though the MACS/WIHS Combined Cohort Study, DC Cohort and HPTN CRS contribute to the Core's capacity to achieve its aims and support the overall mission of the DC CFAR.