We introduce firm and worker heterogeneity into a model of innovation-driven endogenous growth. Individuals who differ in ability sort into either a research sector or a manufacturing sector that produces differentiated goods. Each research project generates a new variety of the differentiated...

We introduce firm and worker heterogeneity into a model of innovation-driven endogenous growth. Individuals who differ in ability sort into either a research sector or a manufacturing sector that produces differentiated goods. Each research project generates a new variety of the differentiated...

Evidence for the United States suggests balanced growth despite falling investment-good prices and less than unitary elasticity of substitution between capital and labor. This is inconsistent with the Uzawa Growth Theorem. We extend Uzawa.s theorem to show that introducing human capital...

Evidence for the United States suggests balanced growth despite falling investment-good prices and less than unitary elasticity of substitution between capital and labor. This is inconsistent with the Uzawa Growth Theorem. We extend Uzawa's theorem to show that introducing human capital...

We develop a model of repeated product improvements in a continuum of sectors. Each product follows a stochastic progression up a quality ladder. Progress is not uniform across sectors, so an equilibrium distribution of qualities evolves over time. But the rate of aggregate growth is constant....