This paper studies the evolution of a competitive industry in which a fixed number of firms reduce costs by innovating and by imitating their rivals' technologies. As the firms' technologies gradually improve, industry output expands and price falls. Technological leaders tend to rely on...

A model of advertising is presented in which consumption experience is an imperfect indicator of product quality. In equilibrium, neither price nor advertising signal the quality of newly introduced goods. Advertising of established products can be a signal of quality, but if it is, it must be...

Three key features of the employment process in the U.S. economy are that job creation is procyclical, job destruction is countercyclical, and job creation is less volatile than job destruction. These features are also found at the sectoral (goods and services) level. The paper develops,...

Firm numbers first rise, then later fall, as an industry evolves. This nonmonotonicity is explained using a competitive model in which innovation opportunities fuel entry and relative failure to innovate prompts exit; equilibrium time paths for price and quantity also share features of the data....