We analyze the dynamics of age-structured population renewal when vital rates make a transition in a finite time interval from arbitrary initial values to any specified final values. The general solution to the renewal equation in such cases is obtained. This solution describes the birth...

This paper examines the long-term impact of constant immigration on the dependency ratio in an SI population (a stationary population through constant immigration) in the context of the stable population model. Our analysis has three main findings. First, in SI populations, a younger population...

Population momentum is the ratio of a population's ultimate size after a demographic transition to its initial size before the transition. For stable population and instantaneous drop to replacement fertility, Keyfitz found a simple formula for the momentum. Although Keyfitz's formula has been...