For more than two decades, the ratio of $50,000 per quality-adjusted life-year (QALY) gained by using a given health care intervention has played an important if enigmatic role in health policy circles as a benchmark for the value of care. Researchers have summoned this cost-effectiveness ratio in order to champion or denounce particular investments in medical technologies and health programs. Critics, meanwhile, have argued that the ratio is misunderstood and misused.