Human Capital, Mortality and Fertility: A Unified Theory of the Economic and Demographic Transition

This paper provides a unified theory of the economic and demographic transition. Individuals make optimal decisions about fertility, education of their children and the type and intensity of the investments in their own education. These decisions are affected by different dimensions of mortality and technological progress which change endogenously during the process of development. The model generates an endogenous transition from a regime characterized by limited human capital formation, little longevity, high child mortality, large fertility and a sluggish income and productivity growth to a modern growth regime in which lower net fertility is associated with the acquisition of human capital and improved living standards. Unlike previous models, the framework emphasizes the education composition of the population in terms of the equilibrium share of educated individuals, and differential fertility related to education. The framework explores the roles of different dimensions of mortality, wages and schooling in triggering the transition. The dynamics of the model are consistent with empirical observations and stylized facts that have been difficult to reconcile so far. For illustration we simulate the model and discuss the novel predictions using historical and cross-country data.