"This paper presents a model in which firms recruit both unemployed and employed workers by posting vacancies. Firms act monopsonistically and set wages to retain their existing workers as well as to attract new ones. The model differs from Burdett and Mortensen (1998) in that its assumptions...

"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...