So the issue here is not simply one of transparency and accountability. In addition, political considerations may be at work. At times, an increase in the unemployment rate may be required to sustain stable, low inflation.
Rare is the leader of a monetary policy committee who relishes going to the legislature and reporting that the central bank is concerned that too many people have jobs. The uncertainty about the threshold unemployment rate also suggests a differing degree of intensity in the response of monetary policy to deviations of inflation and output to their respective targets.