Its dominant role in American medical care underlies the system of specialty medicine, whereby most M.D.'s are specialists and a few are general practitioners. Further, the cost of technology is largely responsible for making the hospital the site of the most advanced medical care. Only hospitals and very large clinics or group medical practices can afford to purchases the most costly equipment. It is beyond the means of individual physicians or small groups. Working Conditions Physicians who practice alone or in small groups generally work long, irregular hours.
Most specialists work fewer hours each week than general practitioners.
As doctors approach retirement age, they may accept fewer new patients and tend to work shorter hours. However, many continue in practice well beyond 70 years of age. Contractual arrangements in the rapidly evolving outpatient care sector vary enormously. An outpatient surgical center, for example, may be operated by several physicians as a group medical practice. Work patterns of such physicians resemble those of other physicians in group practice.