This article examines whether changes in physician reimbursement under the Medicare Fee Schedule (MFS) had differential impacts on access to care for vulnerable ann nonvulnerable Medicare beneficiaries. The quasi-experimental research design takes advantage of cross-sectional differences in the magnitude of the MFS impact on payments. We selected a stratified random sample to ensure adequate representation of vulnerable group members and constructed service-specific measures of the MFS payment change. While we found few effects on access attributable to the MFS, we did find substantial utilization gaps between vulnerable and nonvulnerable subpopulations for primary care services, as well as for high-cost procedures during episodes of care for acute myocardial infarctions
