We test whether occupational licensing undercuts a key goal of digital marketplaces-- to increase social surplus by increasing the effectiveness of customer search. Our setting is a large online marketplace in the $500B home services industry where a platform converts customer search into sales...

This paper develops a new approach to make welfare assessments based on the notion of Dynamic Stochastic weights (DS-weights for short). For a large class of dynamic stochastic economies with heterogeneous individuals, we introduce an aggregate additive decomposition that satisfies desirable...

We develop a general equilibrium geographic framework to characterize the welfare effect of transportation infrastructure investments. We tackle three distinct but conflating challenges: First, we offer an analytical characterization of the routing problem and, in particular, how infrastructure...

This paper summarizes economic research on investment in public infrastructure and introduces the findings of several new studies on this topic. It begins with a review of several potential justifications for the public sector's involvement in building, financing, and operating infrastructure,...

Cities are shaped by transportation infrastructure. Older cities were anchored by waterways. Nineteenth century cities followed the path of streetcars and subways. The 20th century city rebuilt itself around the car. The close connection between transportation and urban form is natural, since...

This paper studies the impact of aid volatility in a two-period model where production may occur with either a traditional or a modern technology. Public spending is productive and "time to build" requires expenditure in both periods for the modern technology to be used. The possibility of a...

Will politics lead to over-building or under-building of transportation projects? In this paper, we develop a model of infrastructure policy in which politicians overdo things that have hidden costs and underperform tasks whose costs voters readily perceive. Consequently, national funding of...

Cities generate negative, as well as positive, externalities; addressing those externalities requires both infrastructure and institutions. Providing clean water and removing refuse requires water and sewer pipes, but the urban poor are often unwilling to pay for the costs of that piping....

The direct benefits of infrastructure in developing countries can be large, but if new infrastructure induces in-migration, congestion of other local publicly provided goods may offset the direct benefits. Using the example of rural household electrification in South Africa, we demonstrate the...