New Keynesian theory identifies a set of principles central to the design and implementation of monetary policy. These principles rely on the ability of a central bank to manage expectations precisely, with policy prescriptions typically derived under the assumption of perfect information and...

We study zero interest-rate policy in response to a large negative demand shock when long-run expectations can fall over time. Because falling expectations make monetary policy less effective by raising real interest rates, the optimal forward guidance policy makes large front-loaded promises to...