The division of labor between and within countries is driven by two fundamental forces, comparative advantage and increasing returns. We set up a simple Ricardian model with a Marshallian input sharing mechanism to study their interplay. The key insight that emerges is that the interaction...

The world is replete with spatial frictions. Shipping goods across cities entails trade frictions. Commuting within cities causes urban frictions. How important are these frictions in shaping the spatial economy? We develop and quantify a novel framework to address this question at three...

The core-periphery model by Krugman (1991) has two 'dramatic' implications: catastrophic agglomeration and locational hysteresis. We study this seminal model with CES instead of Cobb-Douglas upper tier preferences. This small generalization suffices to change these stark implications. For a wide...

Models of the new economic geography share a number of common conclusions, but also exhibit notable differences, in particular with respect to the shape of the location pattern and the efficiency of the market equilibrium. This reflects the fact that these models rely heavily on specific...

We develop a theory of a firm in an environment with incomplete contracts. The firm's headquarter decides on the complexity, the organization, and the global scale of its production process. Specifically, it decides: i) on the mass of symmetric intermediate inputs that are part of the value...

Recent studies indicate that firms often outsource standard and simple tasks, while keeping complex and important inputs inside their boundaries. This observation is difficult to reconcile with the property rights approach of the firm, which suggests that important components should be...

We use unique plant-level data to study the link between the local availability of services and the decision of manufacturing firms to source materials from abroad. To guide our empirical analysis we develop a monopolistic-competition model of the materials sourcing decisions of heterogeneous...

What type of businesses do unions target for organizing? A dynamic model of the union organizing process is constructed to answer this question. A union monitors establishments in an industry to learn about their productivity and decides which ones to organize and when. An establishment becomes...

"Implicit Contracts, incentive compatibility, and involuntary unemployment" (MacLeod and Malcomson, 1989) remains our most highly cited work. We briefly review the development of this paper and of our subsequent related work, and conclude with reflections on the future of relational contract...

This paper provides a simple theory of geographical mobility which simultaneously explainspeople’s choice of residences in space and the location of industry. Residences are chosenon the basis of the utility which mobile households obtain across locations...