An Atlas of US Physician Practice Choice and Firm Structure: 2015-2020, for Selected States from the FTC Physician and Facility Merger Study

In this paper, we describe US physician practices using data from the Federal Trade Commission (FTC)'s Physician Practice and Healthcare Facility Merger Study. The data consists of healthcare claims data from six major insurers in 15 states which collectively account for approximately 80 percent of commercial insured patients between 2015 and 2020. We find that the degree of patient choice of provider practices varies substantially by physician specialty. For instance, 18 percent of primary care is provided to patients in highly concentrated ZIP codes while the share of highly concentrated ZIP codes is much higher for other medical specialties. We also find substantial variation in concentration throughout the study states. Finally, we document the extent to which physician practices exhibit scope with the fraction of physicians working in multispecialty practices or as employees of health systems. We find large variation in scope both by physician specialty and region.