How does the formation of cross-country teams affect the organization of work and the structure of wages? To study this question, we propose a theory of the assignment of heterogeneous agents into hierarchical teams, where less skilled agents specialize in production and more skilled agents...

We propose a theory of firm dynamics in which workers have ideas for new projects that can be sold in a market to existing firms or, at a cost, implemented in new firms: spin-offs. Workers have private information about the quality of their ideas. Because of an adverse selection problem, workers...

A firm's productivity depends on how production is organized given the level of demand for its product. To capture this mechanism, we develop a theory of an economy where firms with heterogeneous demands use labor and knowledge to produce. Entrepreneurs decide the number of layers of management...

We use a simple theory of a system of cities to decompose the determinants of the city size distribution into three main components: efficiency, amenities, and frictions. Higher efficiency and better amenities lead to larger cities but also to greater frictions through congestion and other...

This paper shows how competition for land may lead firms to optimally innovate in spite of the market being perfectly competitive. When bidding for a location, firms can enhance their bid by investing in innovations that make the land more valuable. Firms are willing to innovate because the...

We present a theory of spatial development. Manufacturing and services firms located in a continuous geographic area choose each period how much to innovate. Firms trade subject to transport costs and technology diffuses spatially. We apply the model to study the evolution of the US economy in...

Most economic activity occurs in cities. This creates a tension between local increasing returns, implied by the existence of cities, and aggregate constant returns, implied by balanced growth. To address this tension, we develop a general equilibrium theory of economic growth in an urban...