In the United States, state level boards dictate rules for physician licensure and discipline. Would-be physicians must complete an approved medical training program and pass a standardized test. Scope of-practice laws prohibit other health professionals from offering similar services. Given the resources involved in licensing doctors, taxpayers might be surprised to learn that the link between licensing and service quality is tenuous at best. In fact, economists who have examined the market for physician services generally view medical licensing as a constraint on the efficient combination of inputs and a drag on innovations in health care and medical education.