“Global, regional, and national age-sex-specific mortality and life expectancy, 1950–2017: a systematic analysis for the Global Burden of Disease Study 2017” is based on more data than ever before and includes 622 new data sources, for a total of 8,259 data sources. The 2017 study produced and used a new set of population estimates, which has led to substantial changes in mortality estimates in many countries. The analysis has been extended in time by two decades to start in 1950, and the statistical methods have been improved.