Life quantity, life quality and longevity: the need for an intertemporal evaluation framework

Those of us who have traveled through international airports in the last few years have almost certainly seen the following HSBC ad (quite frequently found on those covered walkways that are used to embark on or disembark from airplanes):“Of all the people in the world who have ever lived to be 65, two-thirds are alive today”.I admit having felt puzzled every time I have seen that ad. I would ask myself: Is this statement saying something good or bad about humanity?One can think of obvious reasons to feel good about the presence of so many older people. Should we not rejoice at the significant increase in life expectancy over the last decades? Should we not be pleased that the earth sustains the lives of an increasing number of human beings?

Duclos, J.-Y., "Life quantity, life quality and longevity: An intertemporal social evaluation framework", Ferdi, policy brief B79, October 2013