Date of Original Version
Journal of Monetary Economics Volume 6, Issue 4, October 1980, Pages 467–492
Abstract or Table of Contents
When changes occur, people do not know how long they will persist. Using a simple stochastic structure that incorporates temporary and permanent changes in an augmented IS-LM model, we show that rising prices and rising unemployment — stagflation is likely to follow a large permanent reduction in productivity. All markets clear and all expectations are rational. People learn gradually the permanent values which the economy will reach following a permanent shock and gradually adjust anticipations. In our model, optimally perceived permanent values take the form of a Koyck lag of past observations.