[File:All Causes world map - DALY - WHO2004.svg|thumb|upright=1.25|Disability-adjusted life years out of 100,000 lost due to any cause in 2004. ]] The disability-adjusted life year (DALY) is a measure of overall disease burden, expressed as the number of years lost due to ill-health, disability or early death. It was developed in the 1990s as a way of comparing the overall health and life expectancy of different countries.