Responding to distortions in payment rates between services, policymakers in the United States have sought a systematic and rational foundation for determining physician fees. One such approach to paying physicians, the Resource-Based Relative Value Scale (RBRVS), determines fees by measuring the relative resource costs required to produce them. On January 1, 1992, the Medicare program implemented a new payment system for physician services based on the RBRVS. This article provides a brief history of the RBRVS and a summary of the methods and data used to derive it. This overview represents the culmination of 6 years of research by the Harvard RBRVS study team and provides a road map to the study's concepts and definitions. The overview also provides a context for the articles in this issue that describe five major studies undertaken since 1988. The study's overall results are presented in the last article of the series.