Which specialties' single-specialty groups depend most heavily on HMOs for their revenue? According to the Medical Group Management Association, it's not necessarily the primary care fields ostensibly prized in managed care for their "gatekeeping" role. In two sets of data — one gathered for a survey and the other culled from the association's membership information — pediatrics and obstetrics/gynecology each attributed a higher proportion of revenue to at-risk managed care than family practice or internal medicine (though these gatekeeper specialties showed higher percentages, in turn, than such fields as cardiology, ophthalmology and orthopedic surgery). One explanation offered by MGMA: Many family physicians and internists do their gatekeeping within multispecialty organizations, so they don't show up in single-specialty group data.

SOURCE: MEDICAL GROUP MANAGEMENT ASSOCIATION, ENGLEWOOD, COLO.