Quality, Quantity and Duration of Lives*

Assessing development and public policies often requires comparing social states that differ in income distributions, population sizes and individuals’ longevity. Depending on the approach taken to weight the quality, the quantity and the duration of lives, global social welfare in 2010 can be deemed to be between 1.8 and 407 times that of 1910. The importance given to the quantity of lives is particularly important in that assessment.