Populations in Transition: Analytic Dynamics

Shripad Tuljapurkar, Stanford University
Nan Li, University of Victoria

Rapid fertility transitions appear to have large effects on national savings, and a growing literature uses simulation methods to examine transition dynamics. We present analytical formulae that show how population numbers and structure change over time when fertility and mortality rates undergo a transition. Our results apply to arbitrary initial age structures and make it possible to compare transition dynamics in among distinct populations and transitional trajectories. These results significantly extend our earlier work, in which we were restricted to stable initial populations. We illustrate the results with specific examples from Latin America and Southeast Asia. We discuss the ways in which these results can be used to advance the analytical modeling of economic impacts of demographic transitions.