 The principal idea behind DALYs is simple. If a woman in Guatemala dies of Chagas disease at age 63, this adds 20 DALYs to the global disease burden because her death is 20 years “premature” as compared to Japanese life expectancy (which is taken as the standard because it is the highest world wide). If a man in Hamburg has an accident that confines him to the wheelchair for the rest of his life, this contributes 0.57 DALYs for each of his remaining life years because the weight for paraplegia is 0.57. Every kind of disease or impairment is thus given a number between 0 and 1 (where 0 = full health and 1 = death) that makes it comparable to other conditions. For example, blindness has a weight of 0.43. As blindness contributes less to the burden of disease than paraplegia, this means that blindness is regarded as the less severe of the two in terms of its reduction of functional capacity (Prüss-Üstün et al. 2003).