ROBUST POLICIES IN A STICKY INFORMATION ECONOMY

Abstract

This paper analyzes the behavior of a central bank under strong (“Knightian”) uncertainty when the short-run trade-off between output and inflation is represented by the sticky information Phillips curve proposed by Mankiw and Reis [Quarterly Journal of Economics 117(4), 1295–1328 (2002)]. By solving the robust control problem analytically, we show why model uncertainty does not affect the optimal monetary policy response to demand and productivity shocks, whereas it causes a stronger reaction of the monetary policy instrument to a cost-push (i.e., markup) shock. Differently from what occurs in sticky price models, the antiattenuation effect can result in a degree of price level stabilization that is greater or less than that experienced in the rational expectation model, depending on the central bank's degree of conservatism. These results dramatically affect the rationale for delegating monetary policy to a central banker more conservative than the society.