Population, Innovation, Competition and Growth with and without Human Capital Investment

This paper analyzes how population and product market competition may interact with each other in affecting the pace of productivity growth. We find that the impact of a change in population (size/growth) and in the degree of market concentration on economic growth varies depending on the structure of the underlying model economy and, more precisely, depending on the presence of purposeful human (versus physical) capital investment, the type of input used in the uncompetitive sector, the form of households’ intertemporal utility and whether product market competition (measured by the elasticity of substitution between differentiated intermediates) is disentangled or not from the input-shares in total income. We also find that only a fully endogenous growth model with purposeful human capital investment at the individual level and a continuum of degrees of inter-generational altruism is simultaneously able to predict an ambiguous link between population and economic growth rates and to display no strong scale effects in economic growth, while keeping the property that positive economic growth is feasible even without any population change. The paper also examines the conditions under which population (size/growth) and product market competition/monopoly power can be complementary factors in economic growth.