It concludes by constructing a simple model in which knowledge flows slowly across national borders but moves easily within borders. We show there is a leadership-followership equilibrium, in which some countries are leaders, others are followers. Contrary to Solow's analysis, there need not be...

Recent accounts suggest the development and commercialization of invention has become more "open." Greater division of labor between inventors and innovators can enhance social welfare through gains from trade and greater economies of specialization. Moreover, this extensive reliance upon...

We first summarize the dominant interpretations of the "frontier" in the United States and predecessor colonies over the past 400 years: agricultural (1610s-1880s), industrial (1890s-1930s), scientific (1940s- 1980s), and algorithmic (1990s-present). We describe the difference between the...

Many economists believe knowledge production generates positive spillovers among knowledge producers. The available evidence, however, is mixed. We argue that spillovers can exist along three dimensions (idea, geographic, and collaboration space). To isolate the key channel through which...

Because of their more limited inequality and more comprehensive social welfare systems, many perceive average welfare to be higher in Scandinavian societies than in the United States. Why then does the United States not adopt Scandinavian-style institutions? More generally, in an interdependent...

This paper assesses the validity and accuracy of firms' backward patent citations as a measure of knowledge flows from public research by employing a newly constructed dataset that matches patents to survey data at the level of the R&D lab. Using survey-based measures of the dimensions of...

Leading empiricists and theorists of cities have recently argued that the generation and exchange of ideas must play a more central role in the analysis of cities. This paper develops the first system of cities model with costly idea exchange as the agglomeration force. Our model replicates a...

We document that the percentage of all U.S. assets that are "safe" has remained stable at about 33 percent since 1952. This stable ratio is a rare example of calm in a rapidly changing financial world. Over the same time period, the ratio of U.S. assets to GDP has increased by a factor of 2.5,...

The generation and implementation of ideas, or knowledge, is crucial for economic performance. We study this process in a model of endogenous growth with frictions. Productivity increases with knowledge, which advances via innovation, and with the exchange of ideas from those who generate them...

We analyze a model economy with many agents, each with a different productivity level. Agents divide their time between two activities: producing goods with the production-related knowledge they already have, and interacting with others in search of new, productivity-increasing ideas. These...