Frictional Labor Markets: Theory and Implications

本项目建立了一个基于信息不完善的摩擦性失业理论。人们认为，对工人来说，观察所有潜在雇主的特点是很昂贵的。相反，他们观察的是一个随机的雇主子集，他们选择了最优的样本量。该模型的均衡表现为摩擦性失业；一些工人失业，而一些符合条件的雇主有空缺职位。然而，该模型的含义更接近于瓦尔拉斯模型的基线，而不是现有的微观基础不那么坚实的摩擦性失业模型。除了得出一些新的和令人惊讶的结论外，这个理论还有一个额外的优势，那就是易于处理。初步研究表明，可以使用该模型来检验风险规避和不完善的劳动收入保险市场对摩擦性失业的影响。当失业的规避风险的工人消费他们的资产时，他们越来越愿意寻找低工资、低生产率的工作，因为那里排队的队伍更短，就业机会更高。因此，最优求职行为意味着，一个短期失业的工人的预期工资，远高于长期失业的人的预期工资，而长期失业的人会变得极度厌恶风险。该模型也可用于研究异质工人如何寻找异质工作。先前的研究主要关注匹配过程，而不是搜索过程，结果表明，无摩擦匹配或分配模型的结论不能在没有额外假设的摩擦环境中延续。然而，通过对摩擦性失业背后的信息不完善进行仔细建模，该理论确立了无摩擦结果可以推广到有摩擦的情况。在任何时候，都有超过5%的美国劳动力遭受摩擦性失业，仅就这个原因而言，了解这一水平是否最佳就很重要。但理解摩擦性失业之所以重要，还有其他原因：市场经济是否会为失业工人提供最优的就业激励，还是人们会低效地寻找、接受不合适的工作，或拒绝合适的工作？摩擦性失业如何影响创造新就业机会或投资人力和物质资本的动机？该项目解决了所有这些问题，初步研究得出的结论与现有文献所建议的结论大相径庭

This project builds a theory of frictional unemployment based on information imperfections. It is assumed that it is costly for workers to observe the characteristics of all potential employers. Instead, they observe a random subset of employers choosing optimally their sample size. The equilibrium of this model exhibits frictional unemployment; some workers are unemployed, while some eligible employers have open vacancies. However, the implications of this model are much closer to the baseline Walrasian model than to existing modals of frictional unemployment with less solid microfoundations. Besides reaching a number of new and surprising conclusions, this theory has the added advantage of tractability. Preliminary research shows the possibility of using this model to examine the implications of risk-aversion and imperfect labor-income insurance markets for frictional unemployment. As unemployed risk-averse workers consume their assets, they become increasingly willing to look for low wage, low productivity jobs where queues are shorter and employment chances are higher. Thus, optimal job search behavior implies that the expected wage of a worker who has been unemployed for only a short period of time, is much higher than the expected wage of the long-term unemployed who grow extremely risk-averse. This model can also be used to study how heterogeneous workers search for heterogeneous jobs. Previous research, which focused on the matching process and not on the search process, showed that the conclusions of frictionless matching or assignment models do not carry over to a frictional environment without additional assumptions. However, by carefully modeling the information imperfections behind frictional unemployment, this theory establishes that frictionless results generalize to a frictional setting. At any point in time, over 5% of the U.S. labor force suffer from frictional unemployment, and for that reason alone it is important to understand whether the level is optimal. But understanding frictional unemployment is important for other reasons: does a market economy give optimal incentives for an unemployed worker to take a job, or do people search inefficiently, accept inappropriate jobs, or reject appropriate ones? How does frictional unemployment affect the incentives to create new jobs, or to invest in human and physical capita1? This project addresses all these issues and preliminary research leads to substantially different conclusions than the existing literature suggests