rule is simple far from guarantees that the rule will generate satisfactory economic outcomes in the face of uncertainty and economic change.
For example, Friedman’s rule would likely perform poorly in an environment in which the trend rate of growth of monetary velocity underwent a major shift, while the Taylor rule could perform unsatisfactorily if the assumption about potential-output behavior embedded in the rule proved to be badly mistaken. The latter possibility was stressed in Orphanides (2003). 15 See Sayers (1958, p. 7).