Policy rules and targets: framing the central banker's problem

The author presents an analytical framework for the formulation of a central bank policy rule and examines some conceptual issues relating to the current debate over the effectiveness of such rules. In discussing the move by many central banks to adopt a price-level or inflation rate target--the basis for one type of rule--he suggests that central banks are implicitly changing the relative importance they attach to the goals of price and output stability. Using 1984-95 data, he shows that an effort to decrease inflation variability modestly could cause output to deviate significantly from its optimal path. The essay also addresses the influence of various types of uncertainty on policymaking, the possible justifications for interest rate smoothing, and the consequences of the fact that nominal interest rates cannot fall below zero.