Rule-of-thumb behaviour and monetary policy

We investigate the implications of rule-of-thumb behaviour by consumers or price setters for optimal monetary policy and simple interest rate rules. This behaviour leads to endogenous persistence in output and inflation and alters the policymaker's welfare objective. Our main finding is that highly inertial policy is optimal regardless of what fraction of agents occasionally follow a rule of thumb. We also find that a first-difference version of Taylor's (Carnegie-Rochester Conf. Ser. Public Policy 39 (1993) 195-214) rule generally has desirable properties. By contrast, the coefficients in other optimised simple rules tend to be extremely sensitive with respect to the fraction of rule-of-thumb behaviour. (C) 2002 Elsevier B.V. All rights reserved.