In this paper, we develop a tractable model of the labor market where workers search for jobs both while unemployed and while on the job. Search is directed in the sense that each worker chooses to search for the offer that provides the optimal tradeoff between the probability of obtaining the offer and the increase in the value relative to the worker's current employment. There are both aggregate and match-specific shocks, on which the wage path in an offer can be contingent. We characterize the equilibrium analytically and show that the equilibrium is unique and socially efficient. On the quantitative side, we calibrate the model to the US data to measure the effect of aggregate productivity fluctuations on the labor market. We find that productivity fluctuations account for approximately 64% of the cyclical volatility in US unemployment. Moreover, productivity fluctuations generate the same matrix of correlations between unemployment and other labor market variables as in the US. In particular, the Beveridge curve is negatively sloped over business cycles, and the magnitude of the slope is the same as in the data. In light of these findings, we conclude that productivity shocks are one of the main forces driving labor market fluctuations over business cycles. Furthermore, we find that recessions have a cleansing effect on the economy.
