This paper develops a dynamic stochastic general equilibrium (DSGE) model with sticky prices and sticky wages, in which agents have imperfect information on the stance and direction of monetary policy. Agents respond by using Kalman filtering to unravel persistent and temporary monetary policy changes in order to form optimal forecasts of future policy actions. Our results show that a New Keynesian model with imperfect information and real rigidities can account for several key effects of an expansionary monetary policy shock: the hump-shaped increase in output, the delayed and gradual rise in inflation, and the fall in the nominal interest rate.

This paper shows that the optimal monetary policies recommended by New Keynesian models still imply a large amount of inflation risk. We calculate the term structure of inflation uncertainty in New Keynesian models when the monetary authority adopts the optimal policy. When the monetary policy rules are modified to include some weight on a price path, the economy achieves equilibria with substantially lower long-run inflation risk. With either sticky prices or sticky wages, a price path target reduces the variance of inflation by an order of magnitude more than it increases the variability of the output gap.