Monetary Policy and the Drifting Natural Rate of Interest
研究发现长期自然利率会受永久性冲击，零利率下限使通胀预期向下偏移，央行需在零利率下限内外都采取扩张性政策来抵消这种偏移。
Abstract Empirical analyses find that the long‐run natural rate is subject to permanent shocks. How should monetary policy react to such shocks? Because of the zero lower bound (ZLB) on nominal interest rates, the mere possibility of future movements toward zero of the long‐run natural rate imparts a downward bias on inflation expectations. To offset this bias, a central bank optimizing under commitment should not only rely on forward guidance at the ZLB, as recommended by the existing literature, but also adopt an expansionary bias away from the ZLB.