Project Summary Elderly patients are particularly susceptible to complications after major surgery, with rates approaching 35%. Such complications threaten independence and carry a higher risk of death, underscoring the importance of careful coordination of care in this population. With ongoing shortages of surgeons across multiple disciplines, some surgical practices have incorporated nurse practitioners (NPs) and physician assistants (PAs) who provide the flexibility of functioning in both the inpatient and outpatient settings. One advantage of this approach includes improved access to the operating room (e.g., by allowing surgeons to perform procedures more efficiently) and clinic (e.g., by offloading selected patient visits). Additionally, this delivery model can enhance care coordination during the index hospitalization, and between the inpatient and outpatient settings, which may improve surgical outcomes. Potential disadvantages of this model relate to the relative inexperience of NPs and PAs with respect to postoperative care, which may result in delayed complication recognition, and the possibility of increased resource use (e.g., through greater use of diagnostic testing and/or consulting physicians). This project comprehensively assesses these issues using national Medicare data and has the following aims: 1) Measure the impact of integration of NPs and PAs into single- specialty surgical practice on access to care for patients with Medicare; 2) Determine the impact of integration of NPs and PAs into single-specialty surgical practice on surgical outcomes; and, 3) Assess the impact of NP and PA integration on practices that disproportionately care for vulnerable Medicare patients. Findings from this study will shed light on how NPs and PAs can be utilized to improve surgical access and outcomes in Medicare patients, and certain vulnerable populations in particular. Furthermore, the project will directly inform policymakers, health system leaders, professional societies and surgeons about the effects of NP/PA expansion on surgical care in the elderly.