Of course, policy commitments can influence future expectations only to the extent that they are credible. Various devices might be employed to enhance credibility; for example, the central bank can make securities purchases or issue financial options that make it quite costly, in financial terms, to renege on its commitments (Clouse et al., 2003).
An objection to this strategy is that it is not entirely clear why a central bank, which has the power to print money, should be overly concerned about its financial gains and losses.