To sign or not to sign: physician participation in Medicare, 1984.

Factors leading physicians to sign the 1984 Medicare participation agreement are assessed in this study. The decision was highly sensitive to Medicare reimbursement levels. A 10-percent increase in the Medicare reasonable charge increased average participation rates by 9.5 percent, or 3.2 percentage points (around the mean of 34 percent). Higher collection costs associated with obtaining that payment from Medicare discourage participation, and physicians with large Medicare caseloads were more likely to participate. Although board-certified physicians were no less likely to participate, graduates from non-English speaking non-Western European medical schools were more likely to sign. Physicians in more liberal States and in areas with greater health maintenance organization activity were significantly more likely to participate, as were those with lower malpractice costs and weaker private demand.