The Design of the RAND Health Insurance Experiment: A Retrospective.

This article, prepared as part of a special issue on multiarmed experiments, describes the design of the RAND Health Insurance Experiment, paying particular attention to the choice of arms. It also describes how the results of the Experiment were used in a simulation model and, looking back, how the design might have differed, and how the results apply today, 4 decades after the Experiment was conducted.