The training is required for certification in a specialty and is approved by a non-governmental accrediting organization for the specialty. The residency program varies in length depending on the specialty. Most residency programs are sponsored by a hospital, medical school, or educational consortium. There are about 100,000 residents in 8,000 different residency programs. The residents, who are serving a form of apprenticeship, provide patient care under the supervision of a teaching physician.
Teaching hospitals serve as the primary training sites for most residency programs.
Training occurs in both the inpatient setting and in the ambulatory-clinics of the teaching hospital. In addition, community hospitals and other community-based sites provide training opportunities. Residency training should be relevant to current daily physician practice and address the care of the individual patient in their cultural and social context. With the growth of managed systems of care and the movement of services to outpatient settings, residency programs have expanded training opportunities in community settings. Under this definition, the processes of care and educational outcomes are the determining factors in identifying a community setting rather than its location per se.