Aging, Secular Stagnation, and the Business Cycle
构建并估计了一个包含人口结构、实际与货币冲击以及零利率下限约束的美国经济模型，发现人口结构变化可解释2019年美国人均产出低于其线性趋势约40%的缺口，且通过压低利率导致零利率下限在大衰退后生效，拖累了复苏速度。
Abstract By the end of 2019, U.S. output was 14% below the level predicted by its pre-2008 trend. To understand why, I develop and estimate a model of the United States with demographics, real and monetary shocks, and the occasionally binding zero lower bound on nominal rates. Demographic shocks generate slow-moving trends in interest rates, employment, and productivity. Demographics alone can explain about 40% of the gap between log output per capita and its linear trend by 2019. By lowering interest rates, demographic changes caused the zero lower bound to bind after the Great Recession, contributing to the slow recovery.