摘要：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
either as standing in for 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
nonlinearity in expectations. The effect of this is to improve policy
performance by focusing agents’ expectations on policy objectives. But
improvements are limited; it does not generally pay to reduce target variability
to zero. More important, this nonlinearity 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 nonlinear process with a linear method, thereby greatly speeding and making
more robust the computation of simulation results.
