On-the-Job Search and Short-Term Employment

本项目探讨了劳动力市场标准宏观经济理论中两个相关假设的重要性：均衡搜索和匹配模型。第一个假设是，工人只有在失业时才能找工作。首席研究员将跟随其他一些研究人员的领导，探索允许“在职”搜索的含义。第二个假设是，企业只有在有职位空缺时才会雇佣工人。PI将探讨允许“短期雇佣”的影响，即企业雇佣一名员工，并知道在不久的将来会找到更好的员工。这种可能性以前没有被研究过。初步研究表明，在职求职和短期就业可能会定性地影响劳动力市场的行为。例如，在标准均衡搜索模型中，所有劳动力增长率的增加（例如，由于婴儿潮）或工作离职率的增加（例如，由于商业周期波动）都会导致失业率的增加。在一个同时考虑在职求职和短期就业的模型中，这种影响可能是相反的。更一般地说，似乎任何增加就业和失业之间工人流动的活动都有降低失业率的潜力。该项目的第一个目标是探索该结果对模型规范的敏感性。在这个项目的过程中，PI将内生工资决定和搜索行为，并将异质工人和工作引入基本模型。然后，他将研究由此产生的经济的性质。该项目的第二个目标是探索在职求职和短期就业理论的宏观经济含义。这一理论将阐明工人在不同工作之间的大规模流动。该研究还预测，工人在工作岗位上停留的时间越长，失去工作的可能性就越小，这与现有的证据是一致的。PI将探讨这对个人失业持续期和总体失业持续期的影响。PI还将调查劳动力市场的僵化（如招聘成本）是否可能是欧洲高失业率的原因。这种可能性是由基本结果提出的，即就业和失业之间的大量工人流动对于保持低失业率很重要。本项目的最后一个目标是使用各种经验证据来检验该理论。例如，指数将利用16-24年前的出生率波动来确定劳动力增长率的预期变化。在职寻找和短期就业理论对这些波动对失业率、工资、劳动力参与率和工人在不同工作之间流动的影响作出了强有力的预测。因此，经验证据最终将完善或拒绝这一理论。

This project explores the importance of two related assumptions in the standard macroeconomic theory of the labor market: the equilibrium search and matching model. The first assumption is that workers can only search for jobs when they are unemployed. The Principal Investigator will follow the lead of some other researchers and explore the implications of allowing for "on-the-job" search. The second assumption is that firms can only hire workers when they have a job vacancy. The PI will explore the implications of allowing for "short-term employment" a situation in which a firm hires a worker knowing that it will try to find a better one in the near future. This possibility has not previously been examined.Preliminary research indicates that on-the-job search and short-term employment may qualitatively affect the behavior of the labor market. For example, in the standard equilibrium search model, all increase in the labor force growth rate (e.g. due to the baby boom) or an increase in the job separation rate (e.g. due to business cycle fluctuations) causes an increase in the unemployment rate. In a model with both on-the-job search and short-term employment, the effects may be reversed. More generally, it appears that any activity that increases the flow of workers between employment and unemployment has the potential of reducing the unemployment rate.The first objective of this project is to explore the sensitivity of this result to the model specification. In the course of this project, the PI will endogenize wage determination and search behavior and will introduce heterogeneous workers and jobs into the basic model. He will then examine the properties of the resulting economy.The second objective of this project is to explore the macroeconomic implications of the theory of on-the-job search and short-term employment. The theory will shed light on the large flow of workers between jobs. It also predicts that the probability of a worker losing her job should get smaller as the worker stays in the job for longer, which is consistent with the available evidence. The PI will explore the implications of this for the persistence of individual unemployment spells and of aggregate unemployment. The PI will also examine whether labor market rigidities such as hiring costs may he responsible for high levels of unemployment in Europe. This possibility is suggested by the basic result that a large flow of workers between employment and unemployment is important for maintaining a low unemployment rateThe last objective of this project is to test the theory using a variety of empirical evidence. For example the PI will use fluctuations in birth rates 16-24 years earlier to identify anticipated changes in the growth rate of the labor force. The theory of on-the-job search and short-term employment makes strong predictions concerning the impact of these fluctuations on unemployment rates, wages, labor force participation, and the flow of workers between jobs. Thus empirical evidence will ultimately refine or reject this theory.