We study the interplay between transportation infrastructure, knowledge flows, and innovation. Exploiting historical data on planned portions of the interstate highway system, railroads, and exploration routes as sources of exogenous variation, we estimate the effect of U.S. interstate highways...

Patents are a useful but imperfect reward for innovation. In sectors like pharmaceuticals, where monopoly distortions seem particularly severe, there is growing international political pressure to identify alternatives to patents that could lower prices. Innovation prizes and other non-patent...

Cumulative innovation is central to economic growth. Do patent rights facilitate or impede such follow-on innovation? This paper studies the effect of removing patent protection through court invalidation on the subsequent research related to the focal patent, as measured by later citations. We...

Large firms spawn spin-outs caused by innovations deemed unrelated to the firm's overall business. Small firms generate demand for specialized services that lower entry costs for others. We study the interplay of these two localized externalities and their impact on regional innovation. We...

We study how fragmentation of patent rights ('patent thickets') and the formation of the Court of Appeal for the Federal Circuit (CAFC) affected the duration of patent disputes, and thus the speed of technology diffusion through licensing. We develop a model of patent litigation which predicts...

We study how the market for innovation affects enforcement of patent rights. Conventional wisdom associates the gains from trade with comparative advantage in manufacturing or marketing. We show that these gains imply that patent transactions should increase litigation risk. We identify a new...