Over the past several years, federal and state policymakers have considered a variety of proposals to increase health insurance coverage among the nation's residents. The federal government has devoted considerable effort, encompassing public health programs and tax incentives, to encourage U.S. residents to obtain health insurance. This book describes a model the Congressional Budget Office (CBO) developed to simulate and analyze an array of policy options involving health insurance coverage. It describes the model's design, basic methodology, and fundamental assumptions. To illustrate the model's use, this book reports estimates for two scenarios in which policy regarding health insurance coverage would differ from current law. This is an edited, excerpted and augmented edition of a Congressional Budget Office report.