Randomized experiments provide policy relevant treatment effects if there are no spillovers between participants and nonparticipants. We show that this assumption is violated for a Danish activation program for unemployed workers. Using a difference-in-difference model e show that the...

Many labor market models use both idiosyncratic productivity and a vacancy free entry condition. This paper shows that these two features combined generate an equilibrium comovement between matches on the one hand and unemployment and vacancies on the other hand, which is observationally...

This paper examines the labour market matching process by distinguishing its two component stages: the contact stage, in which job searchers make contact with employers and the selection stage, in which they decide whether to match. We construct a theoretical model explaining two-sided selection...

The decisions of firms on investment and hiring play a crucial role in business cycle fluctuations. This paper explores their dynamic behavior in the presence of frictions. It does so within a unified framework, stressing their mutual dependence and placing the emphasis on their joint,...

"Many labor market models use both idiosyncratic productivity and a vacancy free entry condition. This paper shows that these two features combined generate an equilibrium comovement between matches on the one hand and unemployment and vacancies on the other hand, which is observationally...

The picture of U.S. labour market dynamics is opaque. Empirical studies have yielded contradictory findings and debates have emerged regarding their implications. This paper aims at clarifying the picture, which is important for the understanding of the operation of the labour market, for the...

This paper presents a theory explaining the labor market matching process through microeconomic incentives. There are heterogeneous variations in the characteristics of workers and jobs, and firms face adjustment costs in responding to these variations. Matches and separations are described...

This paper surveys the use of search and matching models in macroeconomics. It outlines the standard model, discusses its extensions, presents alternative formulations, considers the empirical evidence, and studies applications to macroeconomic questions such as business cycles, growth, and...

This paper studies optimal UI policy from the perspective of worker assignment to heterogenous jobs in an environment of random matching. Workers react to UI policy through job acceptance decisions; firms react to UI policy through wage posting. There is endogenous assortative matching as a...

The labor search and matching model plays a growing role in macroeconomic analysis. This paper provides a critical, selective survey of the literature. Four fundamental questions are explored: how are unemployment, job vacancies, and employment determined as equilibrium phenomena? What...