Increases in health costs continue to outpace general inflation, and implementation of the Patient Protection and Affordable Care Act will exacerbate the problem by adding more Americans to the ranks of the insured. The most commonly proposed solutions--bureaucratic controls, greater patient cost sharing, and changes to physician incentives--all have substantial weaknesses. This article proposes a new paradigm for rationalizing health care expenditures called "relative value health insurance," a product that would enable consumers to purchase health insurance that covers cost-effective treatments but excludes cost-ineffective treatments. A combination of legal and informational impediments prevents private insurers from marketing this type of product today, but creative use of comparative effectiveness research, funded as a part of health care reform, could make relative value health insurance possible. Data deficits, adverse selection risks, and heterogeneous values among consumers create obstacles to shifting the health insurance system to this paradigm, but they could be overcome.