Catalyzing and Harmonizing Operational Innovation for Recruitment (CHOIR) - While recruitment into clinical research has been a longstanding challenge for NIH funded multi-site studies, it has become clear that there is substantial variability in recruitment success across the national portfolio caused by many factors: eligibility parameters, required procedures, compensation levels, engagement practices, recruitment resources, skill and awareness of recruitment teams, geographic constraints, trust, and perceived benefit/risk. Studies that do not integrate these factors into recruitment and retention often close for poor accrual. In addition, there are now more definitions of what constitutes “recruitment success” beyond an absolute target, including: representativeness of the actual population, costs of enrollment, retention, and time required. These complex dynamics suggest there is no ‘one size fits all’ solution, and careful attention and consideration must be a part of the recruitment plan. Our team has been forming effective recruitment collaborations for the past 6 years -- considering the study specifics, capabilities of the study team, and needs and values of the participant population -- to together craft feasible, effective plans. In the next cycle, we will Catalyze and Harmonize Operational Innovation for Recruitment (CHOIR) and will continue to be led by a long-standing synergistic partnership between Paul Harris, PhD, as PI responsible for informatics development, and Consuelo Wilkins, MD, MSCI, as PI of community and stakeholder engagement. Formal partnerships with 10 other CTSAs provide broad understanding of Hub needs, along with key areas of expertise. We will extend and build upon existing recruitment-related assets and data tools and resources already in use by our team and others (FasterTogether, ResearchMatch, REDCap TrialsToday, FHIR clinical data-based recruitment infrastructure). These innovations acknowledge recruitment is not a one-time activity but is a continuum. We will provide a national, disease agnostic home for sharing recruitment tools, training, materials, and best practices for all populations. Specific Aims are: 1) Partner with study teams to create study-specific recruitment plans, and support ongoing skills development. 2) Evaluate clinical trial recruitment and retention methods and make continual improvements.3) Enhance national clinical trial awareness through engagement and education; facilitate participant identification of studies with online tools. And, 4) Develop and disseminate technical and procedural approaches to catalyze enrollment in clinical trials across all CTSAs.