Trend Productivity Growth and Labor Market Frictions in a New Keynesian Business Cycle Model

直到最近，大多数用于货币和财政政策分析的新凯恩斯主义商业周期模型都忽略了两个与经验相关的特征，即趋势生产率增长和失业率。最近的研究讨论了趋势生产率增长和失业的作用，但只是在两种不同的文献中。在具有趋势生产率增长的模型中，劳动力市场仅由于工资刚性而起作用，企业仅根据所谓的密集边际（工作时间）调整劳动力投入。因此，它们不能解释失业率波动和其他劳动力市场结果。包括劳动力市场摩擦在内的模型考虑了失业并产生了产出持续性。然而，它们的定量性质已被证明是反事实的。此外，这些模型中的动态是由暂时的生产率冲击驱动的，与趋势生产率增长无关。因此，他们无法处理诸如趋势生产率增长的变化如何影响失业等问题。该项目的目的是合并这两种文献，目的是建立一个统一的货币和财政政策分析框架，以便：（一）更好地符合诸如失业率波动等固定的事实，以及（二）考虑到商业周期和增长影响之间的相互作用。将针对美国和德国对其他劳动力市场摩擦进行建模和校准，以分析针对临时和永久性冲击的最佳政策反应。

Until recently, most New Keynesian business cycle models used for monetary and fiscal policy analyses have ignored two empirically relevant features, namely, trend productivity growth and unemployment. Recent research has addressed the role of trend productivity growth and unemployment but only within two separate strands of the literature. In models with trend productivity growth, the labor market matters only due to wage rigidity and firms adjust labor input only along what is known as the intensive margin (hours worked). Thus, they can not account for unemployment fluctuations and other labor market outcomes. Models including labor market frictions take account of unemployment and generate output persistence. However, their quantitative properties have been shown to be counterfactual. Moreover, the dynamics in these models are driven by temporary productivity shocks, with no role for trend productivity growth. Consequently, they can not deal with issues such as how a change in trend productivity growth affects unemployment. The project aims at merging the two strands of the literature with the goal of having a unified framework for the analysis of monetary and fiscal policy that (i) better fits the stylized facts, e.g., unemployment fluctuations, and (ii) allows for the interaction of business cycle and growth effects. Alternative labor market frictions will be modelled and calibrated for the US and Germany in order to analyze optimal policy responses to temporary and permanent shocks.