In a very broad class of dynamic linear models, if agents possess knowledge of current endogenous variables in a least-squares learning process, determinacy of a rational expectations (RE) equilibrium is sufficient but not necessary for learnability of that equilibrium. Thus, since learnability...

This paper presents a prototype model for development of the fiscal theory of the price level.' In this simple setting, the fiscal theory's distinctiveness relies upon adoption of a bubble solution, rather than the rational-expectations fundamentals solution. The paper then shows that the fiscal...

This paper investigates the role that imperfect knowledge about the structure of the economy plays in the formation of expectations, macroeconomic dynamics, and the efficient formulation of monetary policy. Economic agents rely on an adaptive learning technology to form expectations and to...

Bennett McCallum (2009), applying Evans and Honkapohja's (2001) results, argues that "learnability" can save New-Keynesian models from their indeterminacies. He claims the unique bounded equilibrium is learnable, and the explosive equilibria are not. However, he assumes that agents can directly...

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...

In a plain-vanilla New Keynesian model with two-period staggered price-setting, discretionary monetary policy leads to multiple equilibria. Complementarity between the pricing decisions of forward-looking firms underlies the multiplicity, which is intrinsically dynamic in nature. At each point...

This paper examines monetary policy in Rudebusch and Svensson's (1999) two equation macroeconomic model when the policymaker recognizes that the model is an approximation and is uncertain about the quality of that approximation. It is argued that the minimax approach of robust control provides a...

This paper addresses the problem of multiple equilibria in a model of time-consistent monetary policy. It suggests that this problem originates in the assumption that agents have rational expectations and proposes several alternative restrictions on expectations that allow the monetary authority...

This paper explores the implications of rational expectations and the aggregate supply theory advanced by Lucas (1973) for analysis of optimal monetary policy under uncertainty along the lines of Poole (1970), returning to a topic initially treated by Sargent and Wallace (1975). Not...

A Keynesian idea of considerable historical importance is that, in the presence of a liquidity trap, a competitive economy may lack--despite price flexibility--automatic market mechanisms that tend to eliminate excess supplies of labor. The standard classical counterargument, which relies upon...