Regression Trees for Estimating Mortality Deceleration and Levelling-off

Mortality deceleration and leveling-off take place for a number of populations, but there are datasets that provide little or no such evidence. As for many contemporary populations, deaths are postponed; we hypothesize that the onset of mortality deceleration is also shifted to higher ages. We use regression trees to estimate the age of mortality deceleration, as well as the onset and level of an eventual mortality plateau for six countries from the Human Mortality Database after 1950. Our preliminary findings show that the onsets of deceleration and leveling-off increase with time, while the level of the plateau is quite stable. For almost all populations after 2000, mortality deceleration starts at age 100 or above, while the plateau is reached at ages above 105.