Physician behavior under the Medicare assignment option.

Using a national sample of general practitioners, internists, and general surgeons, we analyzed the willingness of physicians to accept Medicare patients on assignment. Assignment rates were found to be very sensitive to reimbursement and administrative practices under Medicare. A ten percent increase in the prevailing charge, for example, raised assignment by 14.7 percent. The assigned and non-assigned components of the Medicare program were found to compete with each other; assignment rates were lower where the demand for non-assigned services was stronger. As for the kinds of physicians who take assignment, they were disproportionately general surgeons and foreign medical graduates.