There has been a disparate penetration of health maintenance organizations (HMOs) in urban areas. Whereas only 4.1% of the na? tion's population is enrolled in HMOs, up to 33% of the population of urban areas is en? rolled in HMOs.1 Recent legislative proposals depict HMOs both as struggling unaided in the health care market and as the linchpin in con? sumer choice proposals. Thus, from both a management and a policy perspective, it is im? portant to know whether HMO successes can be attributed to factors that are reproducible in other communities. If they are not, HMOs will become interesting but unimportant phe? nomena.
