Table 1.

Concordance Between Our Composite Coding of Physician Specialty and Coding in the American Medical Association (AMA) Physician Masterfile and the Medicare Database^†

CompositeSpecialty Code*	FamilyPractice, % (n)	GeneralPractice, % (n)	General InternalMedicine, % (n)	Gastroenterology,% (n)	GeneralSurgery, % (n)	ColorectalSurgery, % (n)
Concordance with AMAPhysician MasterfileDesignation	95 (4,367)	79 (612)	91 (7,942)	95 (19,365)	98 (8,325)	88 (2,070)
Concordance withMedicare Self-Designated Specialty	92 (4,437)	58 (913)	71 (11,235)	99 (15,463)	93 (9,197)	97 (1,387)

^*Concordance is defined as the correlation between specialty self-designation codes of Medicare and the AMA Physician Masterfile. There were 1,350 physicians from the AMA Masterfile who were categorized as either “unspecified” or “other.” Similarly, there were 1,399 physicians whose Medicare self-designated code was “multispecialty clinic or group practice,” which did not correspond to the 6 specialties of interest. After applying our specialty designation methodology, we were able to classify all but 74 (0.2%) of the physicians. Those 74 physicians and the procedures they provided were omitted from the analysis.