Inflation Targeting and Target Instability

Monetary policy is modeled as being governed by a known rule, except for a time-varying target rate of inflation. The variable target can be thought of as standing in for either discretionary deviations from the rule, or as the outcome of a policymaking committee that is unable to arrive at a consensus. Stochastic simulations of FRB/US, the Board of Governors' large, rational-expectations model of the U.S. economy, are used to examine the benefits of reducing the variability in the target rate of inflation. We find that putting credible boundaries on target variability introduces an important non-linearity in expectations. The effect of this is to improve policy performance by focussing agents' expectations on policy objectives. But improvements are limited; it does not generally pay to reduce target variability to zero. More important, this non-linearity in expectations allows for policy to be conducted, at the margin, with greater attention to output stabilization than would otherwise be the case. The results provide insights as to why inflation targeting countries use bands and why the bands they use are narrower than studies suggest they should be. A side benefit of the paper is the demonstration of a numerical technique that approximates to arbitrary precision a non-linear process with a linear method, thereby greatly speeding and making more robust the computation of simulation results