A set of indicators for decomposing the secular increase of life expectancy
Valentin Rousson (Centre Hospitalier Universitaire Vaudois, Lausanne)
Friday 13th May, 2011 15:00-16:00 326
Life expectancy almost doubled in developed countries during the 20th century. After an initial increase mainly due to a reduction in infant mortality, two different mechanisms are simultaneously taking place, described by a rectangularization and by a shift to the right of the survival curve. The first mechanism refers to the compression of mortality (or to the concentration of the variable "age at death" around some high value). The second mechanism refers to the increase of the limits of human longevity. In this talk, we propose a set of nonparametric indicators to capture these two trends. Compared to other methods, our indicators have the advantage to fully characterize (conditional) life expectancy, allowing to disentangle and to compare the respective contributions of the two mechanisms above to the secular increase of life expectancy, and hence to quantify (in %) the gain of "life expectancy attributable to rectangularization" (LEAR). A continuous re-assessment of LEAR along the years might be useful to recognize whether the compression of mortality will eventually take place against some ultimate biological limit (in which case LEAR should approach 100%), or towards an ever increasing limit (in which case LEAR will remain below 100%). Applying our indicators to nine Western European countries, we consistently found a value of LEAR close to (or even smaller than) 50%, suggesting that the limits of human longevity are not presently in sight.