K-12 Tax & $pending climate: Across this sample, Wisconsin hospital prices are consistently and substantially higher than prices for the same services in Illinois.

Crowe:
Three central findings emerge:

• Wisconsin hospital prices are roughly 26 percent higher overall. Controlling for the specific service and payer, Wisconsin negotiated rates exceed Illinois rates by approximately 26 percent. The estimate focuses on inpatient (MS-DRG) services, where the premium is +25.6 percent and proves highly stable. The relationship holds across regression specifications, the inclusion of hospital facility-type and teaching-status controls, across the two payers examined, and when reproduced in an independent hospital-reported data source.
• The premium persists within the same health system. Advocate Health operates hospitals on both sides of the Illinois–Wisconsin border. Within this single system, holding corporate governance, brand, and clinical scope constant, Wisconsin hospitals are paid about 23 percent more for inpatient services than the system’s Illinois hospitals.
• The premium is broad and consistent. The two carriers with robust negotiated dollar-value contracts in both states, the Blue plan and UnitedHealthcare, independently show nearly identical inpatient premiums of +25.8 percent and +25.4 percent, indicating that the gap is a feature of the Wisconsin provider market rather than any single insurer’s contracting strategy. Every one of the 24 inpatient procedures examined is more expensive in Wisconsin, spanning obstetric, surgical, cardiovascular, and medical service lines.

Taken together, these findings point to market structure, rather than service mix, hospital type, or insurer behavior, as the leading candidate explanation for Wisconsin’s elevated hospital prices. Subsequent phases will investigate hospital consolidation, service-line restructuring, and the emergence of provider-sponsored health plans as potential structural drivers of these patterns.