Do actuaries believe in longevity deceleration?

Abstract

As more and more people believe that significant life extensions may come soon, should commonly used future mortality assumptions be considered prudent? We find here that commonly used actuarial tables for annuitants – as well as the Lee–Carter model – do not extrapolate life expectancy at the same rate for future years as for past years; instead they produce some longevity deceleration. This is typically because their mortality improvements decrease after a certain age, and those age-specific improvements are constant over time. As potential alternatives (i) we study the Bongaarts model that produces straight increases in life expectancy; (ii) we adapt it to produce best-practice longevity trends (iii) we compare with various longevity scenarios even including a model for “life extension velocity”. (iv) after gathering advances in biogerontology we discuss elements to help retirement systems cope with a potential strong increase in life expectancy.