In the 1970s, researchers at the RAND Corporation conducted a famous social experiment to investigate the relationship between health insurance coverage and health care utilization. In this experiment, samples of individuals were induced to trade their normal insurance policies for new RAND policies that offered different rates at which the insurance would reimburse the individual for health care expenses. In 1993, the Clinton administration used the results of the RAND experiment to predict how health care utilization would increase if insurance cover-age were made universal. What problems might arise in using the social experimentation results to predict the impact of universal coverage?