Using an endogenous growth model, Liu, Mian, and Sufi (2022) (LMS) show that a decline in the interest rate can lead to a fall in productivity growth and a rise in leader-laggard productivity gaps and firm profits. We identify two issues in their quantitative analysis of transition dynamics: a time-scale error and the omission of composition terms in calculating productivity growth along the transition to a new balanced growth path. Correcting the time-scale error and including the composition terms, the decline in the interest rate that LMS study leads to a large and protracted productivity boom lasting about 20 years. In addition, the average leader-laggard gap grows much more slowly than reported in their paper. We also point out an issue in their quantitative analysis of steady-state profit shares. These issues are related to the quantitative exercises, and do not affect the key theoretical contributions of LMS.

中文翻译：

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评论：“低利率、市场力量和生产率增长”

Liu、Mian 和 Sufi (2022) (LMS) 使用内生增长模型表明，利率下降可能导致生产率增长下降以及领先者与落后者生产率差距和企业利润的上升。我们在他们对转型动态的定量分析中发现了两个问题：时间尺度误差和在计算向新的平衡增长路径转型过程中的生产率增长时遗漏了构成项。修正时间尺度误差并包括构成项后，LMS 研究发现利率下降导致了持续约 20 年的大规模且持久的生产力繁荣。此外，领先者与落后者之间的平均差距增长速度比他们论文中报告的要慢得多。我们还指出了他们对稳态利润份额的定量分析中的一个问题。这些问题与定量练习相关，并不影响LMS的关键理论贡献。