Does Competition from HMOs Affect Fee-For-Service Physicians?
NBER Working Paper No. 4920
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 least squares estimates indicate that increases of 10 percentage points in HMO market share are associated with decreases of approximately 11 percent in the normal office visit fee. However, further examination indicates that the incomes of the physicians in the sample are not lower in areas with higher HMO market share. In addition, the quantity of services provided, measured by the number of hours worked and the number of patients seen per week, is not higher in these areas. While it is possible that physicians induce demand to change the volume or mix of services provided to patients in ways that do not affect the number of hours worked or patients seen, another hypothesis consistent with these findings is that FFS physicians respond to competition from HMOs by adopting multi-part pricing strategies in which the price for an office visit is reduced but prices for other services are raised.