The Institute of Medicine's Committee on the Future of Primary Care has provided a definition of primary care that suggests that there are significant differences in problem-solving approaches between the patient-focused family physician and the disease-focused specialist. Family physicians address personal health care needs in the context of a sustained partnership with patients, their families, and the community. Since the problems they see are usually early and undifferentiated, family physicians also deal with greater diagnostic uncertainty. Specialists, whose focus is on disease, organ systems, or investigative procedures, see illnesses at a more advanced stage and generally do not deal with problems beyond the realm of their discipline. They usually do not sustain a partnership with patients, and have a shorter problem list from which to develop a hypothesis and a greater time frame in which to substantiate it. Faced with the same patient problems as specialists, family physicians order fewer tests and procedures, yet produce identical outcomes. Mutual respect for these fundamental differences will lead to improved health care efficiency and effectiveness. In countries where family physicians rather than specialists provide first access to the health care system, health care costs are lower, a phenomenon that may be explained by family physicians' use of simple interventions in solving medical problems. Greater patients satisfaction is also found in systems where family physicians are first-contact providers.