This paper studies localization of academic and industrial knowledge spillovers. Using data on U.S. Research and Development laboratories, that quantify spatial aspects of learning about universities and firms as well as their locations, I find that academic spillovers are more localized than...

The new' economic geography focuses on the footloose-labor and the vertically-linked-industries models. Both are complex since they feature demand-linked and cost-linked agglomeration forces. I present a simpler model where agglomeration stems from demand-linked forces arising from endogenous...

The degree of geographic concentration of individual manufacturing industries in the U.S. has declined only slightly in the last twenty years. At the same time, new plant births, plant expansions, contractions and closures have shifted large quantities of employment across plants, firms, and...

This paper reviews recent academic work on the spatial concentration of entrepreneurship and innovation in the United States. We discuss rationales for the agglomeration of these activities and the economic consequences of clusters. We identify and discuss policies that are being pursued in the...

In Silicon Valley's computer cluster, skilled employees are reported to move rapidly between competing firms. This job-hopping facilitates the reallocation of resources towards firms with superior innovations, but it also creates human capital externalities that reduce incentives to invest in...

An important element of the cost of distance is time taken in delivering final and intermediate goods. We argue that time costs are qualitatively different from direct monetary costs such as freight charges. The difference arises because of uncertainty. Unsynchronised deliveries can disrupt...

Tech clusters like Silicon Valley play a central role for modern innovation, business competitiveness, and economic performance. This paper reviews what constitutes a tech cluster, how they function internally, and the degree to which policy makers can purposefully foster them. We describe the...

Does regional economic integration affect the location of economic activity inside countries? In this paper, I discuss recent academic literature on whether the movement towards free trade in North America has influenced the spatial organization of production in Canada, Mexico, or the United...

The explosion of multinational activities in recent decades is rapidly transforming the global landscape of industrial production. But are the emerging clusters of multinational production the rule or the exception? What drives the offshore agglomeration of multinational firms in comparison to...