Obtaining expert testimony has always been the most difficult part of medical malpractice litigation. Historically, there have been two competing interests: members of a professional group did not want to testify against their colleagues, but they did want to run their competitors out of business. Allopathic physicians were happy to label homeopathic physicians as incompetent, and any physician would dispute the competence of a chiropractor. These rivalries led the courts to use the legal doctrines of the school of practice and the locality rule as the basis for qualifying a person as an expert witness.

The school of practice distinctions also predated modern medical training and certification. At one time medical practitioners were divided into chiropractors, homeopaths, allopaths, osteopaths, and several other schools based on different philosophical and psychological beliefs. Since state legislatures did not discriminate among these different schools of healing, judges were reluctant to allow litigation to be used to attack an approved school. Except for chiropractors, allopathic practices (and osteopaths using primarily allopathic methods) have driven out the other schools of medical practice. The courts retain the traditional school of practice rule when they refuse to allow physician experts to question chiropractic care or chiropractors to testify in cases with physician defendants.

While not as rigidly enforced as the school of practice rule, differentiation of physicians into self-designated specialties is also taken into account. (Self- designated because few state licensing boards recognize specialties or limit physicians’ right to practice the specialties in which they have been trained.) The relevance of the specialty qualifications of an expert witness depend on whether the case concerns procedures and expertise that are intrinsic to the specialty or general medical knowledge and techniques that are common to all physicians. This dichotomy is reflected in strategies for expert testimony. Whether the parties to the lawsuit will stress the specialty or general knowledge depends on the qualifications of the expert that each has retained.