Key Definitions
Active physicians: Physicians who are licensed by one of the 50 U.S. states, the District of Columbia, or Puerto Rico are considered active, provided they are working more than 20 hours per week. Physicians who are retired, semi-retired, temporarily not in practice, or not active for other reasons or who have not completed their graduate medical education are excluded. Active physicians include those working in direct patient care or in administration, medical teaching, research, or other non-patient-care activities. Active physicians include those with an MD or a DO degree. The total number of active physicians may differ among tables in this report as a result of missing information in the data file. For example, to determine the percentage of active physicians who are female, the total number of active physicians excludes people whose sex was not reported in the data file.
Note: The AMA Physician Dataset defines gender as "male" OR "female." Although limited to these categories within our analyses, we acknowledge sex and gender as fluid, non-binary variables.
First-year residents and fellows: Physicians in their first year of a graduate medical education (GME) program in their specialty are considered first-year residents or fellows. In some cases, the resident or fellow may have had prior GME training in a different specialty.
International medical graduate: An individual who graduated from a medical school outside the United States, Puerto Rico,1 or Canada is considered an international medical graduate (IMG). This includes U.S. citizens who completed their medical education outside the United States, Puerto Rico, or Canada. To be eligible for licensure and practice in the United States, all IMGs must be certified by the Educational Commission for Foreign Medical Graduates (ECFMG) and complete a residency training program in the United States. Graduates of Canadian and Puerto Rican medical schools are not considered IMGs because they do not have to be certified by the ECFMG to enter a residency training program in the United States. Please note that although graduates of Canadian medical schools who are practicing in the United States are not considered IMGs or U.S. MDs, they are included in the totals for active physicians. Graduates of Puerto Rican medical schools are considered U.S. MDs.
U.S. DO: A physician who received their DO degree from a U.S. DO-granting school — including in the District of Columbia and Puerto Rico1 — accredited by the American Osteopathic Association Commission on Osteopathic College Accreditation (COCA).
U.S. MD: A physician who received their MD degree from a U.S. medical school — including in the District of Columbia and Puerto Rico1 — accredited by the Liaison Committee on Medical Education (LCME®).
Commonly Used Acronyms
- AAMC: Association of American Medical Colleges
- ACGME: Accreditation Council for Graduate Medical Education
- AMA: American Medical Association
- DO: doctor of osteopathic medicine
- GME: graduate medical education
- IMG: international medical graduate
- MD: doctor of medicine
Practice Specialties
This report presents data for the practice specialties with the largest number of active physicians in 2021, meaning more than 2,500 active physicians. Specialty designations for active physicians rely on the primary specialty selected by the physician on the Census of Physicians administered by the American Medical Association (AMA). Specialty designations for residents and fellows reflect the training program accredited by the Accreditation Council for Graduate Medical Education (ACGME) in which the physician is training.
The AMA Physician Masterfile lists more than 200 specialty categories, and there are more than 140 ACGME specialties and subspecialties. To give a more comprehensive and informative view of the specialty category, we grouped some related specialties together, as shown in the left column of the table below. Specialty groupings used in this report are indicated in the table below.
AAMC, AMA, and ACGME Specialty Groupings
Note: Letters in parentheses are the codes the AMA Physician Masterfile uses for self-designated practice specialties/areas of practice.