 Disability-adjusted life years or DALYs aim to measure burden of disease. The measure was originally developed by Harvard University for the World Bank and World Health Organization (WHO) in 1990 and is now widely used by heath policy researchers for comparisons between countries and over time and as a tool for policy making. It can also be used to measure the effectiveness of interventions, though these are usually health policy rather than medical interventions narrowly construed. The WHO makes regular global disease burden estimates in terms of DALYs at regional and global level for more than 135 causes of disease and injury (Mathers et al. 2002).