Title
On Weak and Strong Population Momentum
Author(s)
Thomas J. Espenshade Thomas Espenshade (Princeton University)
Analia S. Olgiati Analia Olgiati (Princeton University)
Simon A. Levin Simon Levin (Princeton University)
Abstract
This paper decomposes total population momentum into two constituent and multiplicative parts called weak momentum and strong momentum. Weak momentum depends on deviations between a population's observed age distribution and its implied stable age distribution. Strong momentum is a function of deviations between a population's implied stable and stationary age distributions. In general, the factorization of total momentum into the product of weak and strong momentum is a very good approximation. The factorization is exact, however, if the observed age distribution is stable or if initial fertility is already at replacement. We provide numerical illustrations by calculating weak, strong, and total momentum for 176 countries, the world, and its major regions. In short, the paper brings together disparate strands of the population momentum literature and shows how the various kinds of momentum fit together into a single unifying framework.
Creation Date
2009-06
Section URL ID
OPR
Paper Number
opr0901.pdf
URL
https://web.archive.org/web/20150906191108/http://opr.princeton.edu/papers/opr0901.pdf
File Function
Jel
C010, D190, J110, J130
Keyword(s)
population, momentum, fertility
Suppress
false
Series
11