This paper analyzes the constraints imposed on monetary and fiscal policy design by expectations formation. Households and firms learn about the policy regime using historical data. Regime uncertainty substantially narrows, relative to a rational expectations analysis of the model, the menu of...

This paper develops a model of policy regime uncertainty and its consequences for stabilizing expectations. Because of learning dynamics, uncertainty about monetary and fiscal policy is shown to restrict, relative to a rational expectations analysis, the set of policies consistent with...

This paper analyzes the value of communication in the implementation of monetary policy. The central bank is uncertain about the current state of the economy. Households and firms are uncertain about the statistical properties of aggregate variables, including nominal interest rates, and must...

The value of communication in monetary policy is analyzed in a model in which expectations need not be consistent with central bank policy - and, therefore, unanchored - because agents face difficult forecasting problems. When the central bank implements optimal policy without communication, the...

This paper develops a theory of expectations-driven business cycles based on learning. Agents have incomplete knowledge about how market prices are determined and shifts in expectations of future prices affect dynamics. In a real business cycle model, the theoretical framework amplifies and...

This paper proposes a theory of the fiscal foundations of inflation based on imperfect knowledge and learning. The theory is similar in spirit to, but distinct from, unpleasant monetarist arithmetic and the fiscal theory of the price level. Because the assumption of imperfect knowledge breaks...

Standard real-business-cycle models must rely on total factor productivity (TFP) shocks to explain the observed co-movement between consumption, investment and hours worked. This paper shows that a neoclassical model consistent with observed heterogeneity in labor supply and consumption, can...

We calibrate and simulate the model's response to `demand' shocks such as shifts in the marginal efficiency of investment, government spending shocks and news shocks. We show that investment-specific shocks can generate business cycle fluctuations that are broadly consistent with aggregate data.

The modern theory of monetary policy emphasizes the management of expectations. In New Keynesian models frequently used for policy evaluation it is well understood that it is not so much the current interest rate, but instead anticipated movements in future interest rates that are central to...