PROJECT SUMMARY BACKGROUND: Appropriate use of antibiotics reduces resistance and protects patients from unnecessary harm. Important advances in antibiotic stewardship have been achieved in outpatient settings, but little is known about stewardship in the rapidly growing telehealth sector. The Centers for Disease Control and Prevention promotes the ?Core Elements of Outpatient Stewardship?, an evidence-based guidance. The core elements are based on concepts of ?commitment? (a public statement of dedication to judicious prescribing) and ?tracking? (performance feedback). Our pragmatic randomized trials have shown that core element interventions constructed using insights from decision and social psychology can greatly reduce inappropriate prescribing in outpatient settings. Yet these interventions have not been tested in the telehealth sector. As telehealth captures more and more of the outpatient market for acute respiratory visits, the need to adapt the Core Elements to the telehealth environment and test them increases so that patients can receive safe and effective care. RESEARCH STRATEGY: Preliminary analyses of show high rates of antibiotic prescribing and substantial variation within and between providers? prescribing practices. We will identify factors that explain variation in prescribing in a mixed methods analysis of retrospective data and subsequent targeted interviews. These factors will be used to inform the intervention and experimental design of a large-scale pragmatic randomized controlled trial evaluating the effectiveness of the Core Elements. We will assess the heterogeneity of treatment effects on provider subgroups to create evidence-based recommendations for stewardship programs targeting telehealth settings. IMPLICATIONS AND DELIVERABLES: This work will generate a better understanding of prescribing practices in the rapidly growing telehealth sector, including what factors are most associated with antibiotic overuse. Based on this information and relevant findings in decision science, we will adapt interventions tested in outpatient clinics that are consistent with CDC Core Elements to telehealth. We will evaluate interventions in a large-scale randomized controlled telehealth trial. We will evaluate the effectiveness of Core Elements and heterogeneity of treatment effects based on provider subgroups. Future stewardship interventions focused on telehealth settings will have the ability to use our findings to promote judicious use of antibiotics.