The Modal Age at Death and the Shifting Mortality Hypothesis

Vladimir Canudas-Romo, University of California, Berkeley

A mathematical expression for modal age at death is used to calculate the number of deaths at a particular age. Models that capture change in mortality over time show an asymptotic approximation towards a constant number of deaths, and survivors, at the modal age. The bell curve for the number of deaths centered around the modal age at death is also constant, while the modal age moves to higher ages over time. These findings are confirmed through applications to populations with historical mortality data. Results reveal a need to revise the rectangularization hypotheses about approaching a limit for longevity.