The resource-based relative value scale (RBRVS) adopted in Medicare in 1992 was intended to address distortions produced by payments based on physician charges. Medicare and an increasing percentage of private insurers now pay physicians based on the RBRVS payment system, which is maintained by the Centers for Medicare and Medicaid Services (CMS), relying on advice on service valuations by the American Medical Relative Value Scale Update Committee (RUC). The paper describes particular problems with the process used by CMS and the RUC and explains why reimbursement for primary care physicians continues to lag those of other specialties.