A number of authors have attemted to test whether the U.S. economy is in a determinate or an indeterminate equilibrium. We argue that to answer this question, one must be impose a priori restrictions on lag length that cannot be tested. We provide examples of two economic models. Model 1...

We study identiÞcation in a class of three-equation monetary models. We argue that these models are typically not identiÞed. For any given exactly identiffed model, we provide an algorithm that generates a class of equivalent models that have the same reduced form. We use our algorithm to...

This paper develops a model with multiple steady states (low tax and unemployment rate versus high tax and unemployment rate) in which equilibrium selection is not conditioned on a sunspot variable. Instead, large enough shocks initiate unavoidable transitions from one regime to the other. The...