Supply and Demand in Disaggregated Keynesian Economies with an Application to the COVID-19 Crisis
中文摘要
我们在一个包含多个部门、多种要素、投入产出联系、名义工资向下刚性、信贷约束和零下限的细分模型中研究供给与需求冲击。我们运用该模型理解COVID-19危机这一综合性的供给与需求冲击如何影响产出、失业和通胀，并导致紧张与松弛的劳动力市场并存。我们表明，负向部门供给冲击具有滞胀效应，而负向需求冲击具有通缩效应，尽管两者都可能引发凯恩斯式失业。此外，生产中的互补性会放大供给冲击引发的凯恩斯式溢出效应，但会减弱需求冲击引发的凯恩斯式溢出效应。这意味着互补性会降低总需求刺激的有效性。在一个针对美国的程式化定量模型中，我们发现，供给冲击和需求冲击各自解释了2020年2月至5月实际GDP降幅的约一半。尽管凯恩斯式失业高达6%，但这种失业集中于某些市场。因此，总需求刺激的有效性仅为所有劳动力市场均处于松弛状态的典型衰退情形下的四分之一。
Abstract
We study supply and demand shocks in a disaggregated model with multiple sectors, multiple factors, input-output linkages, downward nominal wage rigidities, credit-constraints, and a zero lower bound. We use the model to understand how the COVID-19 crisis, an omnibus supply and demand shock, affects output, unemployment, and inflation, and leads to the coexistence of tight and slack labor markets. We show that negative sectoral supply shocks are stagflationary, whereas negative demand shocks are deflationary, even though both can cause Keynesian unemployment. Furthermore, complementarities in production amplify Keynesian spillovers from supply shocks but mitigate them for demand shocks. This means that complementarities reduce the effectiveness of aggregate demand stimulus. In a stylized quantitative model of the United States, we find supply and demand shocks each explain about one-half of the reduction in real GDP from February to May 2020. Although there was as much as 6 percent Keynesian unemployment, this was concentrated in certain markets. Hence, aggregate demand stimulus is one quarter as effective as in a typical recession where all labor markets are slack. (JEL E12, E23, E24, E31, E32, E62, I12)