This Paper studies the inter-temporal problem of a monopolistic firm that engages in productivity-enhancing innovations to reduce its labour costs. If the level of wages is sufficiently low, the firm's rate of productivity growth approaches the rate of wage growth and eventually the firm reaches...

Identification of the strength of human capital externalities at the aggregate level is still not fully understood. The existing method may yield positive or negative externalities even if wages reflect marginal social products. We propose an approach that yields positive average human capital...

Our model studies the evolution of productivity growth in a competitive industry. The exogenous wage rate determines the firms' engagement in labour productivity enhancing process innovation. There is a unique steady state of the industry dynamics, which is globally stable. In the steady state,...

We combine growth theory with US Census data on individual schooling and wages to estimate the aggregate return to human capital and human capital externalities in cities. Our estimates imply that a one year increase in average schooling in cities increases their aggregate labour productivity by...