Quality-Adjusted Life-Years

The quality-adjusted life year (QALY) is a unit of measurement for valuing health outcomes. It is designed to capture in one single measure an individual's gain in utility from improvement in both quality of life and length of life. Cost-effectiveness ratios using QALYs allow comparisons of value for money of different interventions in different areas of medicine. The article explains how QALYs are constructed and measured and notes a number of assumptions on which the measure builds. The history of QALYs is briefly described, and alternatives to QALYs – healthy year equivalents, disability adjusted life years, and saved young life equivalents – are outlined.