The government's formula for Medicare payment can be a formula for a headache, but at its heart are two principles—it is resource-based, meaning it aims to approximate the resources used by a physician to perform any procedure; and it aims for relative equality across procedures that involve similar skills, techniques, and resources—hence the name, Resource-Based Relative Value Scale (RBRVS), developed by Harvard health economist William Hsiao, Ph.D., in the 1980s.