Douglas Wholey

Health Services Research and Policy
School of Public Health
University of Minnesota
Mayo Mail Code 729,
420 Delaware Street S.E.
Minneapolis, MN 55455-0392

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Institutional Affiliation: University of Minnesota

NBER Working Papers and Publications

May 2006The Welfare Consequences of Hospital Mergers
with Robert Town, Roger Feldman, Lawton R. Burns: w12244
In the 1990s the US hospital industry consolidated. This paper estimates the impact of the wave of hospital mergers on welfare focusing on the impact on consumer surplus for the under-65 population. For the purposes of quantifying the price impact of consolidations, hospitals are modeled as an input to the production of health insurance for the under-65 population. The estimates indicate that the aggregate magnitude of the impact of hospital mergers is modest but not trivial. In 2001, average HMO premiums are estimated to be 3.2% higher than they would have been absent any hospital merger activity during the 1990s. In 2003, we estimate that because of hospital mergers private insurance rolls declined by approximately .3 percentage points or approximately 695,000 lives with the vast majorit...
January 2005Did the HMO Revolution Cause Hospital Consolidation?
with Robert Town, Roger Feldman, Lawton R. Burns: w11087
During the 1990s US healthcare markets underwent a significant transformation. Managed care rose to become the dominant form of insurance in the private sector. Also, a wave of hospital consolidation occurred. In 1990, the mean population-weighted hospital Herfindahl-Hirschman Index (HHI) in a Health Services Area (HSA) was .19. By 2000, the HHI had risen to .26. This paper explores whether the rise in managed care caused the increase in hospital concentration. We use an instrumental variables approach with 10-year differences to identify the relationship between managed care penetration and hospital consolidation. Our results strongly imply that the rise of managed care did not cause the hospital consolidation wave. This finding is robust to a number of different specifications.
October 1999Enter at Your Own Risk: HMO Participation and Enrollment in the MedicareRisk Market
with Jean Abraham, Ashish Arora, Martin Gaynor: w7385
We examine HMO participation and enrollment in the Medicare risk market for the years 1990 to 1995. We develop a profit- maximization model of HMO behavior, which explicitly considers potential linkages between an HMO's production decision in the commercial enrollee market and its participation and production decisions in the Medicare risk market. Our results suggest that the payment rate is a primary determinant of HMO participation, while the price of a supplemental Medicare insurance policy positively affects HMO Medicare enrollment. We also find empirical support for the existence of complementarities in the joint production of an HMO's commercial and Medicare products.

Published: Abraham, Jean, Ashish Arora, Martin Gaynor and Douglas Wholey. "Enter At Your Own Risk: HMO Participation And Enrollment In The Medicare Risk Market," Economic Inquiry, 2000, v38(3,Jul), 385-401.

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