Consequently, the legal standard, known as the "locality rule" came into being which stated that the degree of skill and knowledge of physicians varied widely by geography and demographics. The earliest application of the locality rule came in the late 19th century when a court ruled that the standard of care for a physician ought to be measured against others in the area where the physician practiced.
As medicine evolved, however, standards of practice slowly became homogenized across all communities, rural and urban. This happened because medical specialty and subspecialty organizations developed, and physicians were held to the same practice standards. Training became uniform, with all programs employing the same curriculum, using similar textbooks, and subjecting all doctors-in-training to the same qualifying exams, initially, and for recertification. Since the locality rule existed to essentially protect the country doc, the general practitioners who were not as well trained and did not have easy access to the latest medical knowledge and training, it did not apply to those medical specialists and subspecialists who claimed to have advanced training and unique skills. Thus, by the mid-1960's, in most jurisdictions, these physicians were no longer able to invoke the locality rule when they were sued for malpractice. Instead, they were now required to meet a national standard of practice in their particular specialty. This marked the beginning of the end of the locality rule.
By the 1970's, jurisdictions began modifying the locality rule. One problem the courts faced had to do with whether a medical specialist practicing in a rural area was in any way deprived of the conditions enjoyed by medical specialists practicing in urban areas where teaching centers were located. Their concern was that if the answer was yes, then eliminating the locality rule might discourage medical specialists from practicing in rural areas. Courts eventually decided to compromise and instead of adopting a national standard, they converted the locality rule to a state standard. But over time, it became clear that this made no sense because the standards were truly national standards, and so courts began abandoning the locality and statewide rule for all physicians.
When it became clear by the 1980's that hospitals were being built in rural areas, that demographic trends indicated sufficient medical staffing in rural areas, that mass communication and mass transit eliminated the disadvantages of isolation, that all U.S. physicians were held to the national standard for their respective specialty, then the original rationale for the locality and state rules had disappeared, and the courts began to rely on national standards for each given specialty.
Today, all physicians (except those in Tennessee where state locality rules still exist) are required to demonstrate the same degree of care, skill, knowledge, and training that would be expected of other members of that specialty at a national level. Unfortunately, it is still all too common to see a motion during a medical malpractice action that seeks to invoke the locality rule as a way to disqualify a medical expert's testimony. Fortunately, most courts do not accept this ploy as it has no relevance to medical practice today.