TY  - JOUR
AU  - Shimer,Robert
TI  - The Cyclical Behavior of Equilibrium Unemployment and Vacancies: Evidence and Theory
JF  - National Bureau of Economic Research Working Paper Series
VL  - No. 9536
PY  - 2003
Y2  - March 2003
UR  - http://www.nber.org/papers/w9536
L1  - http://www.nber.org/papers/w9536.pdf
N1  - Author contact info:
Robert Shimer
Department of Economics
University of Chicago
1126 East 59th Street
Chicago, IL 60637
Tel: 773/702-9015
E-Mail: shimer@uchicago.edu
AB  - 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 productivity, while under weak assumptions, search models predict that the vacancy-unemployment ratio and labor productivity have nearly the same variance. I establish this claim both using analytical comparative statics in a very general deterministic search model and using simulations of a stochastic version of the model. I show that a shock that changes average labor productivity primarily alters the present value of wages, generating only a small movement along a downward sloping Beveridge curve (unemployment-vacancy locus). A shock to the job destruction rate generates a counterfactually positive correlation between unemployment and vacancies. In both cases, the shock is only slightly amplified and the model exhibits virtually no propagation. I reconcile these findings with an existing literature and argue that the source of the model's failure is lack of wage rigidity, a consequence of the assumption that wages are determined by Nash bargaining.
ER  -