What allows some accountable care organizations (ACOs) to be successful year after year? How can your ACO’s executive team better understand the financial underpinnings of your ACO’s performance? The models for the Medicare Shared Savings Program and ACO Realizing Equity, Access, and Community Health present significant opportunity, but they also bring considerable financial risk for participating organizations. This case study shows how Milliman tools and analytics can help ACOs develop data-driven strategies to measure provider performance and identify opportunities for continuous improvement in ACO programs under the Centers for Medicare and Medicaid Services.