Defining primary care. Empirical analysis of the National Ambulatory Medical Care Survey

Med Care. 1997 Jul;35(7):655-68. doi: 10.1097/00005650-199707000-00001.


Objectives: Efforts to contain health care costs have increased interest in defining which specialties provide primary care and in developing tools to assess the delivery of primary care services.

Methods: Using data from the 1985-1991 National Ambulatory Medical Care Surveys, the authors examined the activities of 29 physician specialty groups to determine whether the recent Institute of Medicine definition of primary care could be operationalized. Ten elements were identified that addressed comprehensiveness (first-contact care, a Herfindahl Index, previous contact for other problems, prevention, and care through the life cycle), coordination (referrals), continuity (any previous contact), and accessibility (care provided to black patients, those on Medicaid, and patients in rural areas).

Results: Principal component and factor analyses suggested that each element, except care through the life cycle, contributed to the construct of primary care. Principal component analysis enabled ordering of specialties according to their "primary careness," suggesting that specialties other than family/general practice, pediatrics, and internal medicine make significant contributions to primary care. Factor analysis suggested that two factors related to process and content underlie the definition of primary care and emphasize the importance of integration of services provided. This analysis provides a basis for further empirical work to develop measures of primary care performance.

Conclusions: National surveys need to be modified to provide a more comprehensive assessment of primary care in the United States.

MeSH terms

  • Ambulatory Care* / classification
  • Cost Control
  • Data Interpretation, Statistical
  • Factor Analysis, Statistical
  • Health Care Costs
  • Health Care Surveys / standards*
  • Health Workforce*
  • Humans
  • Medicine / classification
  • National Academies of Science, Engineering, and Medicine, U.S., Health and Medicine Division
  • Primary Health Care* / classification
  • Specialization*
  • Specialties, Surgical* / classification
  • United States