Over the course of four HCFO grants, Laurence C. Baker, Ph.D., at Stanford University, has examined how managed care and other market forces affect health care access, costs, and outcomes.

In his first HCFO study, Baker examined the ways in which HMO market penetration influences the adoption and use of MRI technologies. He found that although MRI availability in areas with high HMO market shares grew as fast, or faster, than availability in areas with low market shares between 1983 and 1989, by 1994, high market share areas had significantly fewer MRI machines than areas with low market shares. The gap between high and low market share areas widened over time. "Our findings also indicate that increases in HMO market share are associated with a shift from in-hospital toward out-of-hospital MRI sites," says Baker.

Baker's second HCFO grant studied how managed care activity is measured and if commonly used measures accurately capture important features of health care markets. Key parts of this project focused on whether HMO market share, the most common measure of managed care activity, is correlated with patient reports about whether they have a gatekeeper, have to choose from a panel of physicians, need a referral to see a specialist, and related restrictions on care. Results suggested that high HMO market share is associated with high prevalence of patients perceiving multiple restrictions on patient choices, but that it did not correlate well with the prevalence of patients perceiving some, but few, restrictions. "This suggests that HMO market share is likely to be useful measure for the presence of strong managed care, but may not as accurately capture less restrictive forms of managed care plans," says Baker.

In his last two HCFO research projects, Baker has studied the effect of managed care on Medicaid and Medicare patients. Baker just completed a study examining the relationship between moving from fee-for-service Medicaid to Medicaid managed care and health care access and utilization. Prior to that, he assessed the relationship between area managed care activity and the costs, treatment patterns, and health outcomes for cancer patients covered by traditional, fee-for-service Medicare. "Findings from this study indicate that area levels of HMO activity may influence diagnosis rates for some cancers among non-managed-care patients, perhaps by promoting screening. At the same time, while there were some relationships between area managed care activity and treatment patterns among those patients diagnosed, these results were statistically weaker and less clear," says Baker.

Baker's research interests extend beyond health economics and the effects of managed care on the structure and functioning of the health care system, including the role and effects of regulation in health care, the drivers and impacts of health care technology advancement, health care for newborns, and the ways of the internet and electronic communication influence health care. Baker teaches courses on the health economics, the U.S. health care system, and health policy for medical students and other students at Stanford University.

In addition to being an associate professor of health research and policy and chief of health services research at the Stanford University School of Medicine, Baker is also a fellow of the center for health policy at Stanford University, and holds a position as a research associate in the health care, productivity, and children's programs of the National Bureau of Economic Research in Cambridge, Mass. Baker also holds a courtesy appointment in the Stanford University Department of Economics. Before coming to Stanford, he was a Research Economist at The Robert Wood Johnson Foundation.

Dr. Baker received his M.A. and Ph.D. in Economics from Princeton University, and his B.A. from Calvin College in Grand Rapids, Michigan.

Selected Publications

Baker, L.C. "Managed Care Spillover Effects," Annual Review Public Health, Vol. 24, 2003, pp. 435-56. E-publication, November 6, 2001, Review.

Baker, L.C. "Managed Care and Technology Adoption in Health Care: Evidence from Magnetic Resonance Imaging," Journal of Health Economics, Vol. 20, No. 3, May 2001, pp. 395-421.

Baker, L.C. "Measuring Competition in Health Care Markets," Health Services Research, Vol. 36, April 2001, pp. 223-51.

Baker L.C. "Association of Managed Care Market Share and Health Expenditures for Fee-For-Service Medicare Patients," Journal of the American Medical Association, Vol. 281, No. 5, February 1999, pp. 432-7.

Baker, L.C. And Wheeler, S. "Managed Care and Technology Diffusion: The Case of MRI," Health Affairs, Vol. 17, No. 5, September/October 1998, pp. 195-207.

Baker, L.C. and McClellan, M.B. "Managed Care, Health Care Quality, and Regulation," Journal of Legal Studies, Vol. 30, No. 2, Part 2, 2001, pp. 715-742.

Baker, L.C., "What Does HMO Market Share Measure? Examining Provider Choice Restrictions," in Frontiers in Health Policy, A.M. Garber, Editor. MIT Press: Cambridge, MA. 2000, pp. 91-212.

Baker, L.C. and Phibbs, C.S. "Managed Care, Technology Adoption, and Health Care: The Adoption of Neonatal Intensive Care," Rand Journal of Economics, Vol. 33, No. 3, 2002, pp. 524-548.

Baker, L.C. and Brown, M.L. "Managed Care, Consolidation among Health Care Providers, and Health Care: Evidence from Mammography," Rand Journal of Economics, Vol. 30, No. 2, 1999, pp. 351-374.

Baker, L.C. and Corts, K.S. "HMO Penetration and the Cost of Health Care: Market Discipline or Market Segmentation?" American Economic Review, Vol. 86, No. 2, 1996, pp. 389-394.