Every year, the Health Care Payment Learning & Action Network (HCP-LAN) at https://hcp-lan.org/ conducts a national effort to assess the adoption of alternative payment models (APMs) over time and track progress towards the LAN’s goals. Since its start in 2015, the Measurement Effort has evolved to incorporate data from a large sample of payers that represent nearly 80% of covered Americans, and now serves as the most comprehensive snapshot available for measuring progress on payment reform. In 2018, the LAN began reporting payment data by line of business—Commercial, Medicaid, Medicare Advantage, and Traditional Medicare . . .