Age-specific contributions to changes in the period and cohort life expectancy

Period life expectancy has increased more slowly than its cohort counterpart. This paper explores the differences between life expectancies at a given time (the gap) and the time required for period life expectancy to reach the current level of cohort life expectancy (the lag). Additionally, to understand the disparity between the two life expectancies we identify and compare age-specific contributions to change in life expectancy. Using mortality models and historical data for Sweden, we examine the effect of mortality changes over time. Our results indicate that the widening of the gap between the two life expectancies is primarily a consequence of the dramatic mortality decline at older ages that occurred during the twentieth century. These results imply that the divergence between the two measures is likely to become even greater in the future as reductions in deaths are concentrated at older ages.