Because monetary policy operates with lags, central banks must avoid fixating on the here and now, and instead use imperfect forecasts to anticipate the future effects of their decisions. In the Fed’s case, the presumption that the US will soon approach full employment has caused the so-called dual mandate to collapse into one target: getting inflation back to 2%.
当然，事情没那么简单。货币政策操作存在时滞，因此央行必须避免只着眼于当下，而是要利用不完美的预测来推断它们的决策的未来影响。对美联储来说，美国即将接近充分就业这一前提导致了所谓的双重使命变成了单一目标：让通胀回到2%。