Long-term contracts, imperfect information, and monetary policy

This paper considers the implications of imperfect information for monetary policy in a model with rational expectations and long-term contracts. The source of uncertainty is the inability of the monetary authority and private agents to directly observe systematic aggregate real and nominal disturbances. Imperfect information introduces the possibility of persistence in the departure of output from the natural level which lasts well beyond the wage setting interval, because the filtering process that agents use to estimate the disturbances leads to serially correlated errors in the wage setting process. It also implies that a monetary feedback rule can affect output only if it is tied to unexpected movements in the information variables. The policy issue posed is related to Friedman's original defense of the constant money growth rule, which emphasized uncertainty about the system rather than the neutrality of systematic monetary rules.