This paper presents an equilibrium labor search model in which workers can simultaneously apply to multiple firms to increase their search intensity. They observe firms’ wage postings before choosing where to apply. Owing to coordination frictions, a firm may not receive any applications; otherwise it is able to hire unless all its applicants have better offers. It is shown that the equilibrium converges to the efficient Walrasian outcome as application costs vanish. Even for nonnegligible application costs, the entry of firms, the search intensity, and the number of filled vacancies are constrained efficient. Wage dispersion is essential for constrained efficiency.

Better-informed consumers may be treated preferentially by firms because their consumption serves as a quality signal for other customers. For normal goods this results in wealthy individuals being treated better than poor individuals. We investigate this phenomenon in an equilibrium model of social learning with heterogeneous consumers and firms that act strategically. Consumers search for highquality firms and condition their choices on observed actions of other consumers. When they observe consumers who are more likely to have identified a high-quality firm, uninformed individuals will optimally emulate those consumers. One group of consumers arise endogenously as “leaders” whose consumption behavior is emulated. Follow-on sales induce firms to give preferential treatment to these lead consumers, which reinforces their learning. “One very clear impression I had of all the Beautiful People was their prudence. It may be that they paid for their own airline tickets but they paid for little else.” James Brady, Press Secretary to Ronald Reagan From Superchic, Little, Brown 1974

We develop and analyze a labor market model in which heterogeneous firms operate under decreasing returns and compete for labor by posting long-term contracts. Firms achieve faster growth by offering higher lifetime wages, which allows them to fill vacancies with higher probability, consistent with recent empirical findings. The model also captures several other regularities about firm size, job flows, and pay, and generates sluggish aggregate dynamics of labor market variables. In contrast to existing bargaining models with large firms, efficiency obtains and the model allows a tractable characterization over the business cycle.

We develop and evaluate experimentally a novel tool that redesigns the job search process by providing tailored advice at low cost. We invited jobseekers to our computer facilities for twelve consecutive weekly sessions to search for real jobs on our web interface. For one-half, instead of relying on their own search criteria, we use readily available labour market data to display relevant alternative occupations and associated jobs. The data indicate that this broadens the set of jobs they consider and increases their job interviews especially for participants who otherwise search narrowly and have been unemployed for a few months.

Electronically published December 16, 2016

Two cornerstones of empirical and policy analysis of firms, in macro, labor and industrial organization, are the determinants of the firm size distribution and the determinants of sorting between workers and firms. We propose a unifying theory of production where management resolves a tradeoff between hiring more versus better workers. The span of control or size is therefore intimately intertwined with the sorting pattern. We provide a condition for sorting that captures this tradeoff between the quantity and quality of workers and that generalizes Becker's sorting condition. A system of differential equations determines the equilibrium allocation, the firm size, and wages, and allows us to characterize the allocation of the quality and quantity of labor to firms of different productivity. We show that our model nests a large number of widely used existing models. We also augment the model to incorporate labor market frictions in the presence of sorting with large firms.

We consider a large market where auctioneers with private reservation values compete for bidders by announcing cheap-talk messages. If auctioneers run efficient first-price auctions, then there always exists an equilibrium in which each auctioneer truthfully reveals her type. The equilibrium is constrained efficient, assigning more bidders to auctioneers with larger gains from trade. The choice of the trading mechanism is crucial for the result. Most notably, the use of second-price auctions (equivalently, ex post bidding) leads to the non-existence of any informative equilibrium. We examine the robustness of our finding in various dimensions, including finite markets and equilibrium selection.

We investigate the role of search frictions in markets with price competition and how it leads to sorting of heterogeneous agents. There are two aspects of value creation: the match value when two agents actually trade and the probability of trading governed by the search technology. We show that positive assortative matching obtains when complementarities in the former outweigh complementarities in the latter. This happens if and only if the match-value function is root-supermodular, that is, its nth root is supermodular, where n reflects the elasticity of substitution of the search technology. This condition is weaker than the condition required for positive assortative matching in markets with random search.

This essay surveys the literature on directed search and competitive search equilibrium, covering theory and a variety of applications. These models share features with traditional search theory, but also differ in important ways. They share features with general equilibrium theory, but with explicit frictions. Equilibria are often efficient, mainly because markets price goods plus the time required to get them. The approach is tractable and arguably realistic. Results are presented for finite and continuum economies. Private information and sorting with heterogeneity are analyzed. While emphasizing issues and applications, we also provide several hard-to-find technical results.