Using data to drive action to reduce opioid overdoses in Seattle, WA - Opioid overdoses and deaths continue to increase nationally and in the Seattle area. Despite improvements in our data infrastructure and care continuum locally, significant gaps remain. We propose to use an intensive data to action framework to guide rapid data infrastructure, medical, opioid use disorder treatment, and public health/harm reduction interventions. We will test the impact of these activities on the rates of opioid overdose (fatal and non-fatal) as well as accessing medications for opioid use disorder (MOUD), harm reduction, and other services. In the exploratory R61 phase of this project, year 1, we will bring together a targeted, multi-sectorial group of stakeholders to identify data infrastructure issues and opportunities in order to support near real time data-driven decision-making. We will utilize Continuous Process Improvement (CPI) tools including root cause analysis and plan-do-study-act to monitor and improve data and care delivery system processes. Existing data systems will be used by Public Health-Seattle & King County including: EMS medical incident report forms, mobile integrated health case management data, and King County Medical Examiner Office data for near real time data analyses, visualization, and action planning. Initial service planning and ongoing outcome monitoring will utilize the King County integrated data hub (e.g. jail, substance use disorder/mental health treatment, housing services, Medicaid health care utilization). Each of these initial activities will have specific, concrete measurable milestones that will be met before proceeding to the next phase. For the developmental R33 phase of this project, years 2-5, we plan to create a sub-acute stabilization center (SASC) for people at high risk for opioid overdose, including those who have recently overdosed and are referred and transported by EMS. Services will also be available to those who self-refer or are referred by community agencies. The SASC will leverage the physical infrastructure and clinical expertise of Evergreen Treatment Services, a long-time provider of MOUD and community based outreach in the Seattle area. Research indicates that MOUD supports recovery, improves outcomes, and cuts mortality rates in half. Providing naloxone and other harm reduction supplies in partnership with existing programs will help decrease morbidity and mortality in the short term and may increase engagement and care utilization. The ongoing stakeholder group will utilize the data infrastructure and CPI processes throughout the second phase of the project to adapt services and inform an expanded cascade of care framework. The primary outcomes are to test the impact of the stabilization center on MOUD initiation and retention, acute care utilization (EMS, ED), morbidity, mortality, incarceration, and utilization of housing supports. We will also conduct cost benefit analyses from a public agency perspective.