At the onset of the 20th century, most practicing physicians had received their training in proprietary medical schools, many of which were essentially diploma mills.1 These schools offered a series of lectures over a 1-year period. A minority of physicians had attended university-based medical schools such as Johns Hopkins, which was established in 1893. There were only a few internships available in 1900.2 These internships offered further medical education for new graduates and offered staff help to the hospitals.
After the Flexner report in 1910, 4-year medical schools based on the Hopkins Model gradually began to replace the proprietary schools.3 The number of US medical schools decreased from 161 in 1905 to 81 in 1922.1
By 1914, 75% to 80% of medical school graduates took 1-year internships. In World War I, commissions in the medical corps required a 1-year internship.3
By 1920 the majority of US physicians were general practitioners who had completed 4 years at a university or a proprietary medical school and a 1-year hospital internship. These general practitioners provided the vast majority of medical care in the US until the middle of the 20th century.
There were virtually no specialists in the early 20th century. The first residencies were established in 1927.3 In the 1930s, 13 medical specialties were recognized and specialty boards were established to certify specialists. Just prior to World War II, in 1940, 24% of US physicians were specialists and 76% were general practitioners who performed surgery, delivered babies, and cared for all medical conditions.3
World War II until 1970s
World War II led to profound changes in medical education and medical practice. An expanding system of hospitals and clinics was established to provide complete medical care to 12 million service men. The military recognized physicians who had some evidence of specialty expertise (with or without board certification); they were assigned to specialty care and were given higher military ranks than general practitioners.3
After World War II there was a major shift from general practice to the specialties. In 1959, 75% of internships were rotating; by 1969 the percentage had decreased to 21%.3 Rotating internships and general practice residencies gradually disappeared, replaced by residencies in the specialties. The term “internship” disappeared, replaced by calling the first year of residency PGY 1 (for postgraduate year 1). Medical services for veterans were greatly expanded, and many specialists were recruited to staff veterans’ hospitals and clinics.
Physicians who had served in the military were eligible for the GI bill, which many utilized to undertake specialty residencies. The number of residency positions increased from 5000 in 1940 to 12,000 in 1949 and 25,000 in 1955.4
In 1940 there were 11,860 physicians in internship and residency programs; in 1949 there were more than 23,000; by 1960 there nearly 38,000 in residency programs.3
The largest increase of physicians in residency programs after World War II was in Internal Medicine. In the decade prior to 1941, 808 physicians were certified in Internal Medicine. From 1941 to 1950 more than 4000, and from 1951 to 1960 more than 6000 were certified in Internal Medicine.5 The vast majority of these physicians entered primary care practice as general internists.
There was a similar increase in Pediatrics. In 1940 there were only 373 residency positions in pediatrics. By 1960 there were 1862 positions and in 1970 there were 2920.3 The vast majority of residents entered primary care practice as general pediatricians.
By 1969 the number of physicians practicing primary care as general internists or general pediatrics (19%) equaled the number practicing as general practitioners.3
A new specialty, Family Medicine, was approved in 1969 and offered 3-year residencies in family medicine.
General practitioners gradually disappeared and were replaced by the 3 groups of specialists with 3 or more years of postgraduate training: general internists, general pediatricians, and family physicians, who became the US primary care work force.
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-James E. Dalen, MD, MPH ScD (hon), Kenneth J. Ryan, MD, Joseph S. Alpert, MD
This article originally appeared in the July 2017 issue of The American Journal of Medicine.
