We develop a dynamic model of transitions in and out of employment. A worker finds a job at an optimal stopping time, when a Brownian motion with drift hits a barrier. This implies that the duration of each worker's jobless spells has an inverse Gaussian distribution. We allow for arbitrary...

This paper argues that a broad class of search models cannot generate the observed business-cycle-frequency fluctuations in unemployment and job vacancies in response to shocks of a plausible magnitude. In the U.S., the vacancy-unemployment ratio is 20 times as volatile as average labor...

This chapter assesses how models with search frictions have shaped our understanding of aggregate labor market outcomes in two contexts: business cycle fluctuations and long-run (trend) changes. We first consolidate data on aggregate labor market outcomes for a large set of OECD countries. We...

Leading empiricists and theorists of cities have recently argued that the generation and exchange of ideas must play a more central role in the analysis of cities. This paper develops the first system of cities model with costly idea exchange as the agglomeration force. Our model replicates a...

Does national market size matter for industrial structure? This has been suggested by theoretical work on home market' effects, as in Krugman (1980, 1995). In this paper, I show that what previously was regarded as an assumption of convenience - transport costs only for the differentiated goods...

The increasing returns revolution in trade is incomplete in an important respect there exists no compelling empirical demonstration of the role of increasing returns in determining production and trade structure. One reason is that trade patterns of the canonical increasing returns models are a...

We consider the distribution of economic activity within a country in light of three leading theories - increasing returns, random growth, and locational fundamentals. To do so, we examine the distribution of regional population in Japan from the Stone Age to the modern era. We also consider the...

There are two principal theories of why countries or regions trade: comparative advantage and increasing returns to scale. Yet there is virtually no empirical work that assesses the relative importance of these two theories in accounting for production structure and trade. We use a framework...

This paper extends Lucas and Prescott's (1974) search model to develop a notion of rest unemployment. The economy consists of a continuum of labor markets, each of which produces a heterogeneous good. There is a constant returns to scale production technology in each labor market, but labor...