Why Has the U.S. Economy Stagnated Since the Great Recession?
研究美国经济自2007-2009年大衰退后未能恢复至原增长路径的原因，通过新模型区分永久性冲击与暂时性影响，发现大衰退造成持续负产出缺口而非滞后效应，经济最终恢复至因生产率增长放缓而降低的趋势路径。
Abstract Since the Great Recession in 2007–2009, U.S. real GDP has failed to return to its previously projected path, a phenomenon widely associated with secular stagnation. We investigate whether this stagnation was due to hysteresis effects from the Great Recession, a persistent negative output gap following the recession, or slower trend growth for other reasons. To do so, we develop a new Markov-switching time series model of output growth that accommodates two different types of recessions: those that permanently alter the level of real GDP and those with only temporary effects. We also account for structural change in trend growth. Estimates from our model suggest that the Great Recession generated a large, persistent negative output gap rather than any substantial hysteresis effects, with the economy eventually recovering to a lower trend path that appears to be due to a reduction in productivity growth that began prior to the onset of the Great Recession.