Murray and Lopez are co-founders of the Global Burden of Disease study, a systematic, scientific effort to quantify the comparative magnitude of health loss from all major diseases, injuries, and risk factors by age, sex, and location over time. Their first collaboration in the early 1990s calculated estimates for eight regions, 107 diseases, and 10 risk factors. More than two decades later, the latest edition of the study, now published annually in the international medical journal, The Lancet, covers more than 300 diseases and injuries in nearly 200 countries by age and sex from 1990 to the present, allowing comparisons over time across age groups and among populations. Approximately 3,200 collaborators in 140 nations contribute to what has been recognized as the world’s largest publishing collaboration in science. In recent years, the GBD enterprise has expanded into quantifying sociodemographic inequalities in health and measuring health on the local level by mapping nations in 5×5 kilometer increments. It is coordinated by the Institute for Health Metrics and Evaluation at the University of Washington where Murray serves as Director.