Medicaid participation by medical and surgical specialists.

Most studies of physician participation in Medicaid have focused on primary care physicians, but access by the poor to specialists' services is also a policy concern. This study examined Medicaid participation rates for a national sample of 2291 private practice physicians in nine medical and surgical specialties. Four fifths of the specialists treated at least some Medicaid patients, with an average case load of 11.2% Medicaid patients, rates very similar to those obtained elsewhere for primary care physicians. Surgical specialists, especially ophthalmologists, otolaryngologists, and urologists, were the most willing to participate, and cardiologists were the least willing. Multivariate analysis confirmed the importance of Medicaid programmatic characteristics on both physician entry and level of participation. A 10% increase in the Medicaid fee would raise specialist participation by 3%. Other factors encouraging participation included faster claims processing, fewer limits on the quantity of services covered, and more generous eligibility criteria.