The Merit-Based Incentive Payment System was introduced in 2017 by the Centers for Medicare & Medicaid Services, the primary U.S. public insurer.1 The Merit-Based Incentive Payment System ties payments to a score determined by four categories: cost, improvement activities, promoting interoperability, and quality.2 Scores for each category are aggregated across all physicians in a group, who all then receive the same score. Understanding the association between group size and Merit-Based Incentive Payment System scores has important implications. For example, if larger groups have higher scores, this could imply that larger groups are able to deliver higher-quality care or, alternatively, that they are better able to absorb the costs of implementing Merit-Based Incentive Payment System requirements.
Using the most recent year for which Merit-Based Incentive Payment System scores are publicly available (2021; see https://data.cms.gov/provider-data/dataset/a174-a962) and data on physician specialty (Doctors and Clinicians File; see https://data.cms.gov/provider-data/topics/doctors-clinicians), we identified...
