I consider an economy growing along the balanced growth path that is hit by an adverse shock to its capital accumulation process. The model integrates efficiency wages due to imperfect monitoring of the quality of labor in a search and matching framework with methods of dynamic general equilibrium analysis. I show that, depending on the firms' abilities to assess workers' performance, the discipline device role of unemployment may account for sharp declines in employment and jobless recoveries driven by exceptional increases in the work effort of employees. The model also explains why rigid real wages may prevail in equilibrium: the large movements in unemployment are indeed associated with real wage rigidity, which is generated endogenously by efficiency wages.
