The Natural Rate of Interest and Its Usefulness for Monetary Policy
用DSGE模型估计美国过去20年的自然利率，发现其高度顺周期，在三次衰退中均大幅降至负值，其中大衰退的下降更持久，并讨论了自然利率对货币政策的用处和局限。
We estimate a state-of-the-art DSGE model to study the natural rate of interest in the United States over the last 20 years. The natural rate is highly procyclical, and fell substantially below zero in each of the last three recessions. Although the drop was of comparable magnitude across the three recessions, the decline was considerably more persistent in the Great Recession. We discuss the usefulness and limitations, particularly due to the zero lower bound, of the natural rate for the conduct of monetary policy.