Feedback and the Use of Current Information

The behavior of several stochastic dynamic rational expectations models is studied when policy behavior can be described by a linear rule. Four policy components are distinguished: a current response component, a feedback component, an open-loop component and a stochastic component. Policy is evaluated in terms of the current and asymptotic first and second moments of the state variables. The importance of distinguishing between variability and uncertainty is brought out. The conditional variance is argued to be the appropriate measure of uncertainty. The analysis is applied to a model of foreign exchange market intervention.