<p>The education of allopathic (MD) and osteopathic (DO) physicians in the United States (US) in general required four years of undergraduate study leading to a baccalaureate degree and four years of medical education afterwards. This pattern has been in existence for over a century. However, with scientific medical advances, specialties developed, requiring additional training following graduation in residencies which are from one to seven years in duration. Sub-specialization eventually developed and requires additional years of training in fellowships. The length of medical school education, residencies, and fellowships, evolved over time and gave rise to the need for accreditation agencies which could verify adherence to what became national standards. In tandem, US states and territories, which have the authority to license physicians, developed medical licensure boards which oversaw in-state examinations. This in turn gave rise to a complex system of reciprocity between states. The development of a standard national examination was a slow process first begun by the National Board of Medical Examiners (NBME) whose exam scores were eventually recognized by some states but not by others. In 1973, the Federation of State Medical Boards (FSMB) created a licensure examination known as the Federation Licensing Examination (FLEX). In the early 1990s, agreement was reached to create a uniform national examination sponsored by the FSMB and the NBME which came to be known as the three-step United States Medical Licensing Examination (USMLE). From projections of physician shortages in the 1970’s, the US moved into a projection of physician surplus in the 1980s. The US Department of Health, Education and Welfare established a Graduate Medical Education National Advisory Committee (GMENAC) which was in session from 1976 to 1980. Prominent participants on this committee were the American Medical Association (AMA) and the Association of American Medical Colleges (AAMC). This committee unfortunately and inaccurately concluded that there would be a surplus of 70,000 physicians in the US by 1990. As a result, existing medical schools were requested to reduce entering class sizes, and a moratorium was placed on the development of new medical schools. This policy remained in place for almost 25 years. It was then realized by the organizations that oversaw the accreditation of allopathic and osteopathic medical schools that the US had and would continue to have a shortage of physicians. The AAMC and its accreditor of medical schools, the Liaison Committee on Medical Education (LCME) approved the creation of new medical schools and the expansion of classes in existing ones. This however only resulted in some 7,000 more MDs graduating annually compared to 1980 for a total of 22,000 per year. Accelerating medical school from four to three years has been viewed by some, but not by all medical educators, as a means to increase the supply of physicians and to reduce the cost of education. Supporters also point out that many such pathways lead students into primary care positions where there is a shortage of physicians. However, it is important to note that in recent years, physician assistants (PAs) and nurse practitioners (NPs) have assumed the role of primary care providers in increasing numbers. Since 2015 there has been a growth in accelerated pathways in about 32 of 159 allopathic schools. However, the total number of students in these pathways is often relatively small. While tuition costs are obviously reduced for participants there is little evidence so far that graduates of these programs significantly improve the situation regarding the physician shortage in the US.</p>