QALY (Quality-adjusted life year)

A Quality-Adjusted Life Year (QALY) is one year of life, weighted by your health-related quality of life. A score of 1.0 means one year in perfect health, and 0 means death. (Negative values, for states judged worse than death, are allowed.) You compute a QALY by multiplying the time spent in a health state by its 'utility weight'. That weight usually comes from a questionnaire, like the EQ-5D or SF-6D. Weinstein and colleagues formalized the idea. QALYs anchor cost-effectiveness analyses in health technology assessment. The UK's NICE applies a reference threshold of £25,000 to £35,000 per QALY gained, since April 2026 (up from £20,000 to £30,000). Germany's IQWiG uses an 'efficiency frontier' approach instead of a fixed threshold. For example, a treatment costing £15,000 that yields 2 QALYs works out to £7,500 per QALY. NICE would generally judge that cost-effective.

Last reviewed: June 22, 2026

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