National Averages for Process and Outcome in Radiation Oncology: Methodology of the Patterns of Care Study.

The purpose of this article is to describe the methodology used by the Patterns of Care Study to conduct surveys of the practice of radiation oncology that not only provide national averages for process and outcome measures but also allow comparisons among important subgroups. The article describes how the sample design assures that these analyses are possible and presents methods used for data collection and analysis.