Since the publication (1976) of the classic Lucas critique, researchers in empirical macroeconomics have endeavored to specify models that capture the underlying dynamic decision-making behavior of consumers and firms who require forecasts of future events. Recently, a number of researchers have developed simple models that have become the workhorses for monetary policy analysis. The models vary considerably with regard to optimizing foundations and explicit treatment of expectations. However, relatively little effort has been devoted to testing the empirical importance of the Lucas critique for these simple models. Can one find specifications that are policy-invariant? This paper develops and implements a set of tests for several monetary policy models used extensively in the literature. In particular, we attempt to test the robustness of optimizing versus nonoptimizing models to changes in the monetary policy regime. We present evidence that shows that some forward-looking models from the recent literature may be less stable than their better-fitting backward-looking counterparts.

This paper assesses the importance of the zero lower bound on nominal interest rates for the interest-rate channel of monetary policy. We simulate several interest-rate setting policy rules with either high or low inflation targets. We determine the extent to which the zero bound prevents real rates from falling, thus cushioning aggregate output in response to negative spending shocks. For small temporary and large permanent shocks, the output path with zero inflation lies modestly below that for higher inflation. For large shocks persisting a few quarters, differences in output paths across high- and low-inflation scenarios can be larger.