PROJECT SUMMARY Individuals with Alzheimer's disease and related dementias (ADRD) are increasingly opting to remain in the community, resulting in a heightened reliance on Medicare's skilled home health care services. About a third of all home health recipients have ADRD, highlighting the significance of ADRD within the home health sector. The implementation of the Patient-Driven Groupings Model (PDGM) on January 1, 2020, represents a significant alteration in the reimbursement landscape for Medicare-certified home health agencies. In contrast to the prior volume-driven payment system which incentivized home health agencies to overprovide therapy, the PDGM now pays home health agencies based on patient characteristics at admission. With the PDGM came several significant modifications including: halving episodes of care from 60 to 30 days, reducing the payment rate after the initial 30 days, and diminishing reimbursement rates for community-initiated services. Our research team has previously shown that persons with ADRD use home health care in systematically different ways than persons without ADRD, including requiring longer episodes of care and being more likely to use community-initiated care (vs. post-acute care). As such, it is critical to understand how this significant payment model change will impact home health services for people with ADRD. This study seeks to bridge this knowledge gap by exploring the impact of the PDGM on home health care access and quality for patients with ADRD, pinpointing factors influencing patient outcome disparities, and capturing stakeholder perspectives within the PDGM framework. Our guiding hypothesis is that the PDGM, while designed to enhance home health care delivery for the broader populace, might inadvertently adversely impact care and outcomes for people with ADRD. To delve into this hypothesis, we propose a mixed-methods study. We will employ a dynamic difference-in-difference analytical model, leveraging Medicare claims and related administrative datasets, to estimate the differential impacts of the PDGM on patients with vs. without ADRD. Simultaneously, we will use qualitative data to garner in-depth insights from a range of home health care providers, shedding light on their experiences, challenges, and adaptive strategies within the PDGM context. In summation, this study will offer the first comprehensive, national evaluation of the PDGM's impact on home health care delivery and key outcomes (mortality, hospitalizations, change in function), specifically focusing on people with ADRD. The findings are expected to equip patients, caregivers, home health agencies, and policymakers with robust empirical evidence to guide informed decisions within the evolving home health care environment.