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

"Shimer's calibrated version of the Mortensen-Pissarides model generates unemployment fluctuates much smaller than the data. Hagedorn and Manovskii present an alternative calibration that yields fluctuations consistent with the data, but this has been challenged by Costain and Reiter, who say it...