In a Ramsey policy regime, heterogeneity in beliefs about the potential costs of climate change is shown to produce policy ambiguities that alter carbon prices and taxation. Three sources of ambiguity are considered: (i) the private sector is skeptical, with beliefs that are unknown to the...

We explore Knightian model uncertainty as an explanation for the observed excess persistence and attenuation in estimated interest-rate reaction functions for the United States, relative to what optimal feedback rules would suggest. Two types of uncertainty are identified: (i) unstructured model...

In his 1999 monograph The Conquest of American Inflation Tom Sargent describes how a policymaker, who applies a constant-gain algorithm in estimating the Phillips curve, can fall into the grip of an induction problem: concluding on the basis of reduced-form evidence that the trade-off between...

Typically, the explanatory variables included in a regression model, in conjunction with the omitted relevant regressors implied by the usual error term, have both direct and indirect effects on the dependent variable. Attempts to obtain their separate estimates have been plagued with...

This paper explores Knightian model uncertainty as a possible explanation of the considerable difference between estimated interest rate rules and optimal feedback descriptions of monetary policy. We focus on two types of uncertainty: (i) unstructured model uncertainty reflected in additive...

The normal assumption of full information is dropped and the choice of monetary policy rules is instead examined when private agents must learn the rule. A small, forward-looking model is estimated and stochastic simulations conducted with agents using discounted least squares to learn of a...

In this chapter we show that all the known estimators of the coefficients of econometric models are inconsistent if their coefficients and error terms are not unique. In their stead, we present models having unique coefficients and error terms, with specific applicability to the analyses of...