Disability-Adjusted Life Year (DALY) Disability-Adjusted Life Year Few but definitions not specific enough Children and adults Calculation: DALY = YLL + YLD - The YLL basically correspond to the number of deaths multiplied by the standard life expectancy at the age at which death occurs. The basic formula for YLL (without yet including other social preferences discussed below), is the following for a given cause, age and sex: YLL = N x L where: N = number of deaths L = standard life expectancy at age of death in years. Because YLL measure the incident stream of lost years of life due to deaths, an incidence perspective has also been taken for the calculation of YLD in the original Global Burden of Disease Study for year 1990 and in subsequent WHO updates for years 2000 to 2004. To estimate YLD for a particular cause in a particular time period, the number of incident cases in that period is multiplied by the average duration of the disease and a weight factor that reflects the severity of the disease on a scale from 0 (perfect health) to 1 (dead). The basic formula for YLD is the following (again, without applying social preferences): YLD = I x DW x L where: I = number of incident cases; DW = disability weight; L = average duration of the case until remission or death (years). Prevalence YLD - The recent GBD 2010 study published by IHME in December 2012 used an updated life expectancy standard for the calculation of YLL and based the YLD calculation on prevalence rather than incidence: YLD = P x DW where: P = number of prevalent cases; DW = disability weight. All WHO Global Burden of Disease assessment, also used in SCD studies DALY One DALY can be thought of as one lost year of "healthy" life. The sum of these DALYs across the population, or the burden of disease, can be thought of as a measurement of the gap between current health status and an ideal health situation where the entire population lives to an advanced age, free of disease and disability. Self; Proxy no Multiple countries and cultural groups Health Utility Quality of Life and Care Measure