AAAHC = Accreditation Association for Ambulatory Health Care; ACO = Accountable Care Organization; CMMI = Center for Medicare and Medicaid Innovation; CMS = Centers for Medicare and Medicaid Services; CPC = Comprehensive Primary Care; CPC+ = Comprehensive Primary Care Plus; EHR = electronic health record; FFS = fee for service; IQR = interquartile range; MAPCP = Multi-Payer Advanced Primary Care Practice; NCQA = National Committee for Quality Assurance; PCMH = patient-centered medical home; PCP = primary care practitioner; SSP = Shared Savings Program; TCPI = Transforming Clinical Practice Initiative; TJC = The Joint Commission; URAC = Utilization Review Accreditation Commission.

Note: Table presents the unweighted mean value for each characteristic. Primary care practices include all practices with ≥1 practitioner (defined as a physician, nurse practitioner, or physician assistant) with a specialty of primary care (defined as family practice, general practice, geriatrics, or internal medicine). The 2018 starters represent 11% of all practices, 7% of applicants, and 5% of participants.

Sources: Mathematica’s analysis of data on practice size and ownership from SK&A data; data on the number and characteristics of attributed Medicare beneficiaries from Medicare Enrollment Database and claims data; data on PCMH recognition from NCQA, TJC, AAAHC, URAC, and state-specific data sources; data on Medicare SSP ACO participation from CMS Master Data Management data; data on participation in CMMI’s TCPI, CMMI’s MAPCP, and CPC Classic from CMS; data on meaningful use of EHRs from CMS Medicare EHR Incentive Program; county data from the Area Resource File.

↵a Table includes 16,883 of the 19,809 primary care practices in the 2017 and 2018 regions because we excluded 2,926 practices (15%) that had no attributed Medicare FFS beneficiaries in the baseline year.

↵b A total of 4,599 practices applied for CPC+. The number of applicants in this table (4,346) is fewer because some applicants could not be identified in the SK&A data, and some applicants had no attributed Medicare FFS beneficiaries at baseline.

↵c The baseline year is 2016 for the 2017 starters and 2017 for the 2018 starters.

↵d In the SK&A data, a practice can be owned (or managed) by a health system and owned by a hospital.

↵e A practice was considered to have PCMH recognition if ≥1 of its primary care practitioners had recognition at some point in 2014-2017 for the 2017 starters and 2015-2018 for the 2018 starters from a state, the AAAHC, TJC, NCQA, or URAC.

↵f We considered a practice to be a MAPCP participant if it participated in any year from 2011-2014, as determined by a file from CMS.

↵g Participants include all those practices that stayed enrolled in CPC Classic for at least the first 5 months.

↵h At least 1 practitioner attested to meaningful use under the Medicare EHR Incentive Program from 2011-2015 for 2017 starters and 2011-2016 for 2018 starters.

↵i Reflects 2014 data for the 2017 starters and 2015 data for the 2018 starters.

↵j The urbanicity of a practice’s county (rural, urban, suburban) is derived from the 2013 (latest year available) rural-urban continuum codes (https://www.ers.usda.gov/data-products/rural-urban-continuum-codes/documentation/) available in the Area Resource Files for both 2017 and 2018 starters.