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...

We develop a two-country model of endogenous innovation and imitation in order to study the interactions between these two processes. Firms in the North race to bring out the next generation of a set of technology-intensive products. Each product potentially can be improved a countably infinite...

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....

In industries with imperfect consumer information, the lack of a reputation puts latecomers at a competitive disadvantage vis-a-vis established firms. We consider whether the existence of such informational barriers to entry provides a valid reason for temporarily protecting infant producers of...

We study the positive and normative effects of counterfeiting, i.e.,trademark infringement, in markets where consumers are not deceived by forgeries.The fact that consumers are willing to pay more for counterfeits than for generic merchandise of similar quality suggests that they value the...

We study a simple, two-stage, stochastic patent race involving two firms. We examine the behavior of the participants as they gain the lead or fall behind in the race. We find that the leader engages in R&D more intensively than does the follower, and that both firms intensify their efforts if...