Optimal Monetary Policy Under Parameter Uncertainty In A Simple Microfounded Model

This paper examines optimal monetary policy under uncertainty about fundamental parameters of a dynamic stochastic general-equilibrium model. In contrast to previous studies, a microfoundation of the model leads this uncertainty to generate uncertainty not only about the transmission of monetary policy but also about the transmission of shocks and about a social welfare loss function. In the presence of such uncertainty, this paper finds conditions under which optimal discretionary policy responds to shocks more aggressively than in the absence of the uncertainty. These conditions depend crucially on the persistence of shocks and the magnitude of policy multipliers. To obtain the conditions, taking proper account of uncertainty about the transmission of shocks and about the welfare loss function is of crucial importance.