The Mankiw-Romer-Weil Model with Decreasing Population Growth Rate

Abstract

This paper studies an extension of the Mankiw-Romer-Weil growth model by departing from the standard assumption of constant population growth rate. More concretely, this rate is assumed to be decreasing over time and a general population growth law verifying this characteristic is introduced. In this setup, the model can be represented by a three dimensional dynamical system which admits a unique solution for any initial condition. It is shown that there is a unique nontrivial equilibrium which is a global attractor. In addition, the speed of convergence to the steady state is characterized, showing that in this model this velocity is lower than in the original Mankiw-Romer-Weil model.