This paper develops county-level estimates of HMO market share for all counties in the United States and uses them to examine the relationship between HMO market share and the fee for a normal office visit with an established patient charged by 2,845 fee-for-service (FFS) physicians. Two-stage...

Increasing managed care activity could influence the adoption and diffusion of new medical technologies. This paper empirically examines the relationship between HMO market share and the diffusion of magnetic resonance imaging (MRI) equipment. Across markets, increases in HMO market share are...