Project Summary/Abstract Most Medicaid beneficiaries receive coverage through a private Medicaid Managed Care (MMC) plan. MMC plans compete for enrollees by offering high quality coverage with access to desirable providers. States use competitive bidding to select high quality, low-cost MMC plans for enrollees to choose from. Plan choice and competitive bidding can promote quality and efficiency in MMC if enrollees sort into high quality plans and/or states are willing to exclude low quality plans from their Medicaid programs. Both these mechanisms may require enrollees to switch plans, which could also negatively affect quality if patients lose access to providers or experience disruptions in their care due to these transitions. Despite the large and growing role of MMC in covering vulnerable populations, little is known about how switching between MMC plans affects health care quality or utilization. Data limitations, unstable enrollment, and state- level policy differences make it difficult to produce evidence on how Medicaid patients’ health care use changes after enrolling in a new MMC plan. This study examines the effect of plan switching among people covered by Minnesota Health Care Programs (MHCP), Minnesota’s set of Medicaid, Children’s Health Insurance Program, and Basic Health Plan options. I will evaluate the impact of changing MMC plans on (1) longitudinal continuity of care and (2) utilization outcomes, including outpatient visits, emergency room use, hospital admissions, and preventable hospital admissions. My empirical strategy focuses on people enrolled in MMC plans that were dropped from MHCP following Minnesota’s competitive bidding process. Between 2014 and 2016, more than 400,000 people were forced to enroll in a new MHCP plan because their previous plan did not bid on, or failed to win, a state contract to offer MMC coverage. I will use a difference-in-differences framework to compare outcomes among enrollees who experienced these “forced switches” to enrollees whose MMC plan remained available. Data for this project comes from the Minnesota All Payer Claims Database. Findings from this study will inform state policy makers and practitioners about the impact of plan switching on health care access and quality for Medicaid patients. The results will help improve state health care programs by evaluating how plan choice and contracting policies affect continuity of care and health care use.