The Medicaid-to-Medicare fee index measures each state's physician fees relative to Medicare fees in each state. The Medicaid data are based on surveys sent by the Urban Institute to the forty-nine states and the District of Columbia that have a fee-for-service (FFS) component in their Medicaid programs (only Tennessee does not). These fees represent only those payments made under FFS Medicaid. Medicare fees were calculated by the Urban Institute using the 2008 Clinical Diagnostic Fee Schedule and the relative value units (RVUs), conversion factor, and geographic adjusters as published in the Federal Register. The Medicaid-to-Medicare fee index is a weighted sum of the ratios of each state's Medicaid fee for a given service to the Medicare fee, using 2000 expenditure weights.

Stephen Zuckerman, Aimee Williams, and Karen Stockley, "Medicaid Physician Fees Grew By More Than 15 Percent From 2003 to 2008, Narrowing Gap With Medicare Physician Payment Rates," Health Affairs, April 2009; available at http://www.kff.org/medicaid/kcmu042809oth.cfm.