The starting point of this PhD dissertation is related to the Shimer puzzle, i.e. the unability of the search and matching model to reproduce the high volatility of the unemployment rate. Real wage rigidities were considered as the main solution to this puzzle. Nevertheless, Sveen and Weinke (2008) argue that those rigidities would not have any impact on the unemployment volatility when hours per worker are determined by the firms. In the first chapter, we argue that the capacity of real wage rigidities to solve the puzzle critically depends on the way that rigidities are introduced. When real wage stickiness results from the «credible bargaining» (Hall and Milgrom ,2008), we show that the unemployment volatility is magnified, even for hours being firms’ decisions. A significant stabilization trade-off between inflation and unemployment is moreover restituted. However, we stress in the second chapter that the credible bargaining delivers a moderate degree of wage rigidity and then requires unrealistic values for some parameters to completely replicate the unemployment volatility. We integrate asymmetric information into this framework and show that the resulting higher wage stickiness fully reproduces the volatility for a plausible calibration. ln the last chapter, we emphasize that it is possible to solve the puzzle without resting on real wage stickiness, by considering a particular calibration of the model with endogenous separations. We also highlight a central mechanism of this framework, for which the volatility of the separation rate amplifies that of the job finding rate.
