Resident-to-resident aggression (RRA) in long-term care (LTC) is associated with preventable injury, suffering, and serious psychological distress. One in five residents in nursing homes (NH) experiences RRA in a given month. Residents with Alzheimer’s Disease and Related Dementias (ADRD) are at an even higher risk of RRA due to cognitive impairment-related symptoms. However, RRA remains poorly understood. Differences in the backgrounds and life experiences of residents may play an important role in RRA initiation and escalation, risk/resilience factors, consequences, and NH response systems. The goal of this project is to systematically investigate differences in resident background and life experiences in the types, patterns, and circumstances surrounding RRA using the first prevalence cohort study of RRA, and collecting additional stakeholder input with explicit consideration of the needs of residents with ADRD, to develop, refine, and pilot-test a novel intervention. In Aim 1, I will leverage the first and only NIH-funded RRA prevalence cohort study to qualitatively contextualize and quantitatively examine the role of background and life experience differences between residents in RRA across individual, dyadic, and facility levels. In Aim 2, I will gather input from multiple NH stakeholders to improve understanding of the role of background and life experience differences in RRA, and to identify current and optimal intervention and prevention strategies in residents with and without ADRD via mixed methods approach. In Aims 3a and 3b, findings from Aim 1 and Aim 2 will be used to develop and refine a staff education intervention focused on RRA between residents from different backgrounds and life experiences that may be integrated into an existing RRA intervention program. As a social scientist trained in public health research, I am ideally positioned to spearhead this line of research, given my productive track record in elder mistreatment research. Through the award period, I will build upon my prior training to develop new knowledge and skills in long-term care research (Aim 1; Training Objective 1); research on population-level health differences (Aim 1; Training Objective 2); long-term care policy-making, advocacy, and leadership (Aim 2; Training Objective 3); and behavioral intervention and implementation science (Aim 3a, 3b; Training Objective 4). Career development activities will consist of formal coursework, experiential learning and research opportunities, and mentorship from experts in elder mistreatment, RRA research, and behavioral intervention development. This award will help me achieve my long-term career goal of being an independent investigator with an impactful program of long-term care research focused on impact-driven, evidence-based elder abuse prevention and intervention development and implementation for older persons with ADRD.