From the report: "After decades of evolution and experiment, the U.S. health care system has yet to solve a fundamental challenge: delivering quality health care to all Americans at an aff ordable price. In the coming years, new solutions will be explored and older ideas revisited. One idea that has returned to prominence is cost sharing, which involves shifting a greater share of health care expense and responsibility onto consumers. Recent public discussion of cost sharing has often cited a landmark RAND study: the Health Insurance Experiment (HIE). Although it was completed over two decades ago, in 1982, the HIE remains the only long-term, experimental study of cost sharing and its eff ect on service use, quality of care, and health. Th e purpose of this research brief is to summarize the HIE’s main findings and clarify its relevance for today’s debate. Our goal is not to conclude that cost sharing is good or bad but to illuminate its eff ects so that policymakers can use the information to make sound decisions."