On human capital and economic growth with random technology shocks

We embed the Uzawa-Lucas human capital accumulation technology into the Mankiw-Romer-Weil exogenous growth model. The paper is divided into two parts. In the first part we assume that the rate of technological progress is exogenous and deterministic and study the local dynamics of the model around its steady-state equilibrium. The first order conditions lead to a system of four nonlinear differential equations. By reducing the dimension of the system to three, we find that the equilibrium is a saddle point. If the equations system is attacked in its original dimension, and by making use of an arbitrage condition, we prove that the equilibrium is unstable. In the second part of the paper technology is assumed to be subject to random shocks driven by a geometric Brownian motion. Using the Hamilton-Jacobi-Bellman equation, and through numerical simulations, we discuss the effects of technology shocks on the optimal policies of consumption and the allocation of human capital across sectors.