Living cohorts

Life expectancy figures can be misleading. For instance, people born in 1930 in France had a life expectancy of about 55 years, but if we follow those people it turned out they lived to 69 years old on average. The difference is period life expectancy versus cohort life expectancy. Period life expectancy assumes everyone born in a particular year will have the same mortality rate as the current population. But cohort life expectancy is the average lifespan of a birth cohort. The difference between the two is caused by mortality rates dropping over time and past conditions influencing the period life expectancy rate e.g., pandemics or wars (clearly visible in in the 1910s and 1940s). If we assume mortality rates continue to decrease and we have fewer mass death events, then the children born today will live to be much older than the current oft-quoted life expectancy figures suggest.

Source: Human Mortality Database, 2023.