The Disability Adjusted Life Year (DALY) is calculated as:

• A Years of Life Lost (YLL) + Years Lived with Disability (YLD) ✓
• B Potential Years of Life Lost (PYLL) / Disability weight
• C Quality Adjusted Life Years (QALYs) - Years with full health
• D Years of Life Lost (YLL) × Disability weight

Explanation

DALY = YLL + YLD, where YLL measures the years of life lost due to premature mortality (compared to standard life expectancy) and YLD measures the years lived with a disability weighted by the severity of the disability (disability weight 0–1). One DALY represents one year of 'healthy life' lost. QALYs are distinct — they measure the benefit of an intervention (years of good quality life gained). DALYs measure burden; QALYs measure gain. The global burden of disease study uses DALYs extensively.

Reference: Park's Textbook of Preventive and Social Medicine, 27th ed.

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Written and medically reviewed by the StethoPrep medical team.