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

直到最近，用于货币和财政政策分析的大多数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率的作用，但仅限于两个不同的文献线索。在生产率呈趋势增长的模型中，劳动力市场之所以重要，只是因为工资刚性，而且企业只会沿着所谓的密集边际(工作时间)来调整劳动力投入。因此，他们无法解释失业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问题，并产生产出持续性。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性的生产率冲击驱动的，对趋势生产率增长没有影响。因此，他们无法应对趋势生产率增长的变化如何影响失业率等问题。该项目旨在将这两类文献结合起来，目的是建立一个分析货币和财政政策的统一框架，以便(1)更好地符合程式化的事实，例如失业波动；(2)考虑到商业周期和增长效应的相互作用。针对美国和德国的替代性劳动力市场摩擦将被建模和校准，以分析应对暂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.