The role of firm entry and firm heterogeneity for monetary and fiscal policy

在货币经济周期文献中，劳动力市场中的广泛边际，即，工人的雇用和解雇，已经得到了广泛的分析。然而，当涉及到产品市场时，广泛的利润率，即，产品的市场进入和退出，仍然是研究不足。分析产品进入和退出的现有模型的一个最重要的和实质性的缺点是，它们没有考虑到重要的经验事实，即新产品的市场份额远远小于市场份额的成熟产品。我们建议开发一个货币的商业周期模型与异质性企业，说明这一事实。在我们的模型中，新产品的生产效率将低于现有产品，而以前的新产品的生产效率会随着时间的推移而提高。初步工作表明，在这种类型的模型中，总生产率是内生的，通货膨胀和产出的商业周期动态受到其构成的严重影响。构成效应是产品进入时自然产生的，它反映了随着时间的推移，资源从生产率较低的产品线向生产率较高的产品线分配的情况。我们将使用包含异质性企业和内生总生产率的货币经济周期模型，分析财政和货币政策的各个方面。与总生产率是外生的现有模型不同，我们的模型将使我们能够追踪财政和货币政策对总生产率水平的影响。因此，它将使我们能够理解这些政策如何影响总生产率在我们目前观察到的大衰退之后恢复到正常水平的路径，这是一个紧迫的问题。

In the monetary business-cycle literature, the role of the extensive margin in labor markets, i.e., the hiring and firing of workers, has been analyzed extensively. When it comes to product markets, however, the role of the extensive margin, i.e., the market entry and exit of products, still remains under-researched. One overriding and material shortcoming of existing models that analyze product entry and exit is their failure to account for the important empirical fact that the market share of new products is much smaller than the market share of established products.We propose to develop a monetary business-cycle model with heterogeneous firms that accounts for this fact. In our model, new products will be produced less efficiently than established products, and the production efficiency of formerly new products improves in the course of time. Preliminary work suggests that in models of this type, the aggregate productivity is endogenous and the business-cycle dynamics of inflation and output are grossly affected by its composition. The compositional effect arises naturally from product entry and captures that over time, resources are allocated from less to more productive product lines.We will use our monetary business-cycle model with heterogeneous firms and endogenous aggregate productivity to analyze various aspects of fiscal and monetary policy. In contrast to existing models in which aggregate productivity is exogenous, our model will allow us to trace out the impact of fiscal and monetary policy on the level of aggregate productivity. Hence, it will allow us to understand how these policies influence the path of aggregate productivity back to its normal level in the wake of a great recession like the one that we currently observe, and this is an urgent matter.