There is a unique threshold age separating early deaths from late deaths such that averting an early death decreases life disparity, but averting a late death increases inequality in lifespans.

In a heterogeneous cohort, the change with age in the force of mortality or some other kind of hazard or intensity of attrition depends on how the hazard changes with age for the individuals in the cohort and on how the composition of the cohort changes due to the loss of those most vulnerable...