Simple versus optimal rules as guides to policy$

This paper compares the performance of different policy rules. Our comparisons focus on simple feedback rules versus rules which are optimal, given knowledge of the correct economic structure and the appropriate loss function for the policymaker. First, we compare rule performance when the correct model is not known. Second, we compare rule performance with respect to the frequency-specific behavior for variables of interest. Taken as a whole, our results indicate how the case for a model-specific optimal rule can break down when one relaxes the assumption that the true model is known as well as the assumption that the appropriate loss function is known. Links are made to the literature on monetary policy. r 2007 Elsevier B.V. All rights reserved.