Project Summary/Abstract The suffering caused by Alzheimer's disease (AD) is one of the greatest medical challenges of our time. With a heightened sense of urgency, numerous AD prevention trials are being launched, requiring an unprecedented number of healthy older adults to be screened to identify the thousands eligible to participate. At the same time, the number of trials in affected individuals and their care partners continues to rise. In 2019, there were 156 trials for the treatment of AD, an increase from 2018. Notably, this number does not include observational studies, which are also important to understanding AD and developing new interventions to treat or prevent it. Improving participant recruitment methods has become a critical priority for the field. Initiatives such as the National Plan to Address AD call for greater attention to increasing enrollment into clinical trials and other clinical research. An outgrowth of the National Plan is the National Strategy for Recruitment and Participation in Alzheimer's Disease Clinical Research which enumerated four goals, one of which is focused specifically on the need to ?build and improve research infrastructure of registries in order to recruit and retain more and more diverse qualified study participants.? The objective of this proposal is to develop, deploy, optimize and automate new website design/content, infrastructure and functionality to support and sustain online recruitment, engagement, and retention of adults interested in participating in AD-focused studies, creating a sustainable and enduring resource to researchers. To accomplish this, we will build off our successful Alzheimer's Prevention Registry (APR), an online registry launched in 2012 with >350,000 members, including ~90,000 enrolled in its GeneMatch (GM) program launched in 2015 via the following aims: 1) develop, deploy, optimize and automate a refreshed and sustainable website platform for the recruitment into and engagement of members in the APR and its GM program; 2) develop, deploy, optimize and automate a refreshed website platform supporting researchers' efforts to recruit APR and GM members; and 3) develop, deploy, optimize and automate new functionality and processes for referring APR and GM members to AD- focused studies. We hypothesize that the a) refreshed website will increase enrollment into the APR and GM as well as engagement and retention of members; b) enhanced AD-Researcher experience will increase the number of researchers / study sponsors leveraging the APR/GM for their participant recruitment needs, allowing them to complete enrollment faster; and c) new functionality will increase the percentage of APR and GM members screening for and enrolling in AD-focused studies.