Technically, the state-contingent evolution that is implemented by commitment to the
policy rule is optimal from a “timeless perspective” of the kind proposed in Woodford
(1999a), which means that it would have been chosen as part of an optimal commitment at a
date sufficiently far in the past for the policymaker to fully internalize the implications of the
anticipation of the specified policy actions, as well as their effects at the time that they are
taken. This modification of the concept of optimality typically used in Ramsey-style analyses
of optimal policy commitments allows a time-invariant policy rule to be judged optimal and
eliminates the time inconsistency of optimal policy. See Giannoni and Woodford (2002a) and
Svensson and Woodford (chap. 2 in this volume) for further discussion.