Quality-adjusted life year [QALY]

The quality-adjusted life year (QALY) is a measure in health economics. It expresses the additional number of years which a person lives as a result of receiving a treatment, and takes into account the quality of life of those years. It does this by measuring how important various factors are to patients, such as symptoms, pain, and psychological health.

The calculation of QALYs is a common approach used by health technology assessment (HTA) bodies, which advise about the ‘usefulness’ of treatments and, in some countries, about whether treatments should be funded by (for example) government health departments.