Where does adaptation to innovation take place? The author presents evidence on the role of agglomeration economies in the application of new knowledge to production. All else equal, workers are more likely to be observed in new work in locations that are initially dense in both college...

Negative demand shocks have afflicted many American cities in the 20th century and are the main explanation for their decaying housing markets. But what is the role of housing supply? Rational entrepreneurs should not invest in new buildings and renovation when home values are below replacement...

Congestion pricing has long been held up by economists as a panacea for the problems associated with ever increasing traffic congestion in urban areas. In addition, the concept has gained traction as a viable solution among planners, policymakers, and the general public. While congestion costs...

We develop a new dynamic general equilibrium model to explain firm entry, exit, and relocation decisions in an urban economy with multiple locations and agglomeration externalities. We characterize the stationary distribution of firms that arises in equilibrium. We estimate the parameters of the...

This paper examines the role local labor markets play in the production of innovations. The authors appeal to a labor market matching model (á la Berliant, Reed, and Wang 2004) to argue that in dense urban areas, workers are more selective in their matches and are therefore more productive....

Despite much theorizing about the role of geographic concentration of employment in knowledge spillovers, local densities' role in promoting innovations has largely been unexamined. More often, studies have considered the effects of city size variables on innovative activity, although the role...

The authors examine portage sites in the U.S. South, Mid-Atlantic, and Midwest, including those on the fall line, a geomorphologic feature in the southeastern U.S. marking the final rapids on rivers before the ocean. Historically, waterborne transport of goods required portage around the falls...