International comparisons are often difficult to interpret, because definitions of terms and reliability of data as well as cultures and values differ. What is important in one society may be unimportant or even nonexistent in another. A political or human right that is important in one nation may be meaningless in a neighboring state. Evaluating the quality of health care systems is an example of the difficulties involved in comparing one culture to another.

Even within the United States, there are cultural and regional variations in health care delivery. A visit to a busy urban urgent care center might begin with the patient completing a brief medical history, five or ten minutes with a nurse who measures and records the patient's vital signs (pulse, respiration, temperature), and conclude with a fifteen-minute visit during which the physician diagnoses the problem and prescribes treatment. In contrast, on the islands of Hawaii, a visit with a healer may last several hours and culminate with a prayer, song, or an embrace. Hawaiian healers, called "kahunas," are unhurried and offer an array of herbal remedies, bodywork (massage, touch, and manipulative therapies), and talk therapies (counseling and guidance) because they believe that the healing quality of the encounter, independent of any treatment offered, improves health and well-being.

While comparing the performance of health care systems and health outcomes (how people fare as a result of receiving health care services) is of benefit to health care planners, administrators, and policymakers, the subjective nature of such assessments should be duly considered.