The Cyclical Behavior of Labor Markets

摘要提案编号：0351352机构：芝加哥大学NSF认证：ECONOMIC 夏默，罗伯特JTITLE：0351352这项研究旨在提高我们对宏观经济学和劳动经济学交叉点上的基本问题的理解-为什么总体冲击主要影响就业而不是工资。搜索模型将这个问题分为两个：（1）为什么这么多工人在经济衰退期间失业，而不是接受减薪？ (ii)为什么公司在经济衰退期间不创造更多的新职位空缺，因为他们预计失业工人愿意以低工资工作？本研究关注的是后一个问题，这个问题近年来受到的关注相对较少。本研究首先记录了经济衰退期间和之后的低水平空缺创造，以及随之而来的高失业时间。 研究证实，在最近的经济衰退中，高失业持续时间比高失业率相对更重要。一个需要解释的强有力的现象是，自二战以来的每次衰退中，失业持续时间都在增加，空缺失业率都在下降。 目前的经济学理论，如劳动力市场搜索和匹配模型，无法解释这一现象。这项研究将开发出替代理论，可以解释为什么在经济衰退期间，空缺创造福尔斯下降如此之多，而工资下降如此之少。初步研究发现了四个富有成效的途径，进一步的工作，将在本研究中进行理论和经验。首先，如果匹配函数在失业和空缺之间表现出足够的替代性，那么空缺的强顺周期性可能是经济对劳动生产率波动的最佳反应。 或者，如果失业和空缺是互补的，波动是次优的，并可能在商业周期的频率非常昂贵。其次，如果衰退是平均生产率较低但工人对公司层面的实际生产率高度不确定的时期，工人可能最好拒绝接受减薪，尽管总失业率很高。第三，在职求职可能会在商业周期频率上改变求职人群的构成，从而放大和传播冲击。最后，异质性工人与异质性工作匹配的时间变化可能会显著增加外生冲击或诱发内生经济周期波动。这项研究可以产生新的见解，匹配模型，适用于其他领域，以及导致新的数学工具，将在经济学中普遍有用。本研究的结果也将有助于劳动力市场政策的评估。

ABSTRACTPROPOSAL NO: 0351352INSTITUTION: University of ChicagoNSF PROGRAM: ECONOMICSPI: Shimer, Robert JTITLE: 0351352This research seeks to improve our understanding of fundamental questions at the intersection of macro and labor economics---why aggregate shocks primarily affect employment rather than wages. Search models break that question into two: (i) why do so many workers lose their job during a recession rather than take a wage cut? (ii) why don 't firms create more new job openings during recessions in anticipation of unemployed workers be willing to work at a low wage? This research focuses on the latter question, which has received relatively little attention in recent years.This research first documents the low level of vacancy creation, and consequenthigh unemployment duration, during and immediately after a recession. Research confirms that high unemployment duration has become relatively more important than high unemployment incidence during recent recessions. A robust phenomenon that needs an explanation is that unemployment duration has increased and the vacancy-unemployment ratio has fallen in every recession since World War II. Current economic theory, such as labor market search and matching models, are incapable of explaining this phenomenon. This research will develop alternative theories that can explain why vacancy creation falls so much and wages fall so little during a recession. Preliminary research has uncovered four fruitful avenues for further work that will be pursued both theoretically and empirically in this research. First, if the matching function exhibits sufficient substitutability between unemployment and vacancies, strong procyclicality of vacancies may be an optimal response of the economy to fluctuations in labor productivity. Alternatively, if unemployment and vacancies are complements, fluctuations are suboptimal and potentially very costly at business cycle frequencies. Second, if recessions are periods with low average productivity but also a high degree of worker uncertainty about actual productivity at the firm level, workers may optimally refuse to accept wage cuts despite high levels of aggregate unemployment. Third, on-the-job search may amplify and propagate shocks by changing the composition of the searching population at business cycle frequencies. Finally, time variation in the matching of heterogeneous workers to heterogeneous jobs may significantly increase exogenous shocks or induce endogenous business cycle fluctuations. This research could yield new insights into matching models that are applicable in other areas as well as lead to new mathematical tools that will be useful in economics generally. The results of this research will also help in labor market policy evaluation.