PROJECT SUMMARY Alzheimer’s disease and related disorders (ADRD) research represents a major national investment. ADRD clinical research faces delays and risks to internal and external validity resulting from challenges to efficient accrual, especially inadequate inclusion of populations at increased risk for disease due to social determinants of health. Recruitment registries are tools to accelerate accrual in ADRD research. Registries are repositories of potentially eligible individuals who have consented to be contacted about studies, reducing the need for serial recruitment by enabling bolus enrollment of ready cohorts. Few data address essential questions about registry design, conduct, and effectiveness in aiding ADRD research recruitment. How best to recruit and retain participants to registries and whether registries can address the urgent need to diversify clinical research samples are unknown. Furthermore, how registry samples compare to other research populations has not been investigated. This proposal investigates traditional and modern approaches to registry recruitment and asks critical questions about inclusion of participants from underserved neighborhoods and registrant retention. Given that registries are, by definition, convenience samples, we also aim to quantify the bias associated with these recruitment tools and develop methodology for addressing this bias. This project will produce essential information about resource utilization in recruitment registries and provide critical guidance for the field about how best to use these important tools.