On the other hand, a flatter Phillips curve means that, once inflation shifts outside the range, bringing it back is that much harder, since the output gap or the change in the output gap necessary to raise or lower the inflation rate becomes correspondingly larger.
For example, in the United States, Governor Mishkin of the Federal Reserve Board, in his speech delivered in April, stated that "returning inflation too quickly to levels consistent with price stability might unnecessarily exacerbate the economic weakness. Instead, while restoring price stability remains critical, the central bank should do so at a pace that does not do undue harm to the economy."