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 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....

Recent developments in the theory of economic growth and dynamic trade theory are reviewed and interpreted. These include growth based on economies of scale, trade with product development, and product cycles. It is argued that there is need for more work in this area in order to understand the...

Chamley (1986) and Judd (1985) showed that, in a standard neoclassical growth model with capital accumulation and infinitely lived agents, either taxing or subsidizing capital cannot be optimal in the steady state. In this paper, we introduce innovation-led growth into the Chamley-Judd...

Schumpeterian growth theory has "operationalized" Schumpeter''s notion of creative destruction by developing models based on this concept. These models shed light on several aspects of the growth process which could not be properly addressed by alternative theories. In this survey, we focus on...

We develop a model with a finite number of multi-product firms that populate an industry together with a continuum of single product firms, and study the dynamics of this industry that arises from investments in the invention of new products. Consistent with the available evidence, the model...

We study a two-country two-sector model of international trade in which one sector produces homogeneous products while the other produces differentiated products. The differentiated-product industry has firm heterogeneity, monopolistic competition, search and matching in its labor market, and...

"Is inequality largely the result of the Industrial Revolution? Or, were pre-industrial incomes and life expectancies as unequal as they are today? For want of sufficient data, these questions have not yet been answered. This paper infers inequality for 14 ancient, pre-industrial societies using...

We develop a framework for studying trade in vertically and horizontally differentiated products. In our model, consumers with heterogeneous incomes and tastes purchase a homogeneous good as well as making a discrete choice of quality and variety of a differentiated product. The distribution of...

In this paper we develop a multi-sector general equilibrium model of firm heterogeneity, worker heterogeneity and labor market frictions. We characterize the distributions of employment, unemployment, wages and income within and between sectors as a function of structural parameters. We find...