There is a paucity of quality of life (QoL) measures for persons living with Alzheimer?s disease and Alzheimer?s disease-related dementias (AD/ADRD) (hereafter called PWD). Without them, we cannot assess the effectiveness of interventions, policies, or health system investments that aim to improve QoL for PWD. Such measures must acknowledge a person?s preferences and well-being, as well as dynamic changes such as where they live and receive care day-to-day. Staying in one?s home remains the dominant preference among PWD. Therefore, if more home time reflects higher quality of life, ?home time? outcome measures are firmly person-centered and could assess population health using ubiquitous claims data. No consensus exists, however, on what health care settings to include in a home time measure. A key reason for our incomplete understanding is that we lack the perspectives of key stakeholders?PWD and their family and friends who help them (caregivers). Nor do we know which definitions of home time most closely relate to person-centered outcomes (PCOs) that matter to PWD. The overarching goal is to arrive at a home time measure that most closely reflects quality of life for PWD and to identify intervenable risk factors that could increase QoL by increasing home time. Importantly, distinct preferences will likely merit a caregiver-version that most closely reflects their QoL. In Aim 1, we will engage a stakeholder panel and then hold in-depth interviews to identify how quality of life for PWD and for their caregivers varies depending on the PWD?s time spent in different health care settings (e.g. emergency department, outpatient surgery, inpatient, nursing home, and assisted living). In Aim 2, we will use mixed methods to develop a single home time measure for PWD that is most closely reflective of PCOs known to matter to PWD (and a separate measure for caregivers). We will link survey data with Medicare and Medicaid claims to allow a more thorough examination of candidate settings than has ever occurred. We will integrate Aim 1 data and validation results from quantitative analyses in order to finalize a home time measure for PWD and one for caregivers. In Aim 3, we will explore how intervenable risk factors that contribute to low QoL for PWD and their caregivers relate to the newly developed home time measures. Because we do not yet understand the relative importance of home, clinical, and social risk factors or how they operate together to jointly influence home time, we will use machine learning to identify impactful risk factors. Advancing the science of home time measurement is urgent, not only for Persons living with Alzheimer?s disease and Alzheimer?s disease-related dementias (AD/ADRD) and caregivers, but also for health systems, given that CMS has launched demonstration programs proposing use of a home time measure as a performance metric for payment policy design. A Policy Convening meeting will help us disseminate best practices for use of the home time measure(s) and minimize negative unintended consequences of any nationally disseminated performance measure. In addition, identifying intervenable risk factors that could be addressed to increase home time for PWD will inform future interventions and practice changes.