PLOS Medicine gives the highest priority to papers on the conditions and risk factors that cause the greatest losses in years of healthy life worldwide. For a guide to the conditions and risk factors that we prioritize, see Tables 1.1 and 1.2 of Global Burden of Disease and Risk Factors. Within these priority areas we make decisions based on whether papers are likely to directly and substantially affect clinical practice or public health policy, or have implications of broad general interest for the direction of future, directly clinically relevant research. In addition, we seek to publish papers that address important topics in the ethics and reporting of medical research.