Gompertz–Makeham law of mortality.

About Gompertz–Makeham law of mortality

The Gompertz–Makeham law of mortality is a mathematical model for the age pattern of death rates. It expresses the force of mortality as the sum of two components: an age-dependent term, the Gompertz function, that increases approximately exponentially with age, and an approximately age-independent background term known as the Makeham term. In populations where deaths from external causes are rare, the background component is often small and mortality can be well described by the simpler Gompertz law of mortality.