Macroeconomics of Occupational Mobility: New Facts, Theory, and Quantitative Evaluation

当一个工人改变职业（例如，销售代表、机械师、出租车司机）时，她通常会改变她所从事的工作类型，而在以前的职业中积累的特定技能可能会有重大损失。然而，换工作的工人比例非常大——在美国，每年有近20%的工人换工作。此外，工人流动的规模大大超过了适应职业就业份额变化所需的再分配量。为什么工人跳槽这么频繁？对整体经济的影响是什么？政府是否有干预的作用？拟议研究的目的是为这些问题提供答案。PI使用了100%丹麦人口的行政小组数据，记录了一组新的事实，描述了职业流动的模式。他发现工人在其职业的工资分布中所处位置的职业转换概率呈u型。在他们的职业中，工资最高或最低的工人离开这个职业的可能性最大。在其职业中相对工资较高（较低）的工人倾向于转向平均工资较高（较低）的职业。当同一职业的相对生产率下降（上升）时，收入较高（较低）的工人往往会离开该职业。这些先前未知的事实并没有被现有的职业流动性理论所暗示，这些理论大多将职业视为水平分化的任务集。PI表明，将职业也视为形成垂直等级可能是有益的。不确定自己能力的员工可以通过观察他们的产出实现情况来了解自己的能力。每个职业的就业机会都很少，导致工人之间的竞争。在生产函数中，工人的能力和一种职业的生产率之间具有互补性，这促使工人根据他们的预期能力将其分类到职业中。PI开发了一个具有这些特征的职业选择均衡模型，并分析表明它与上述流动模式一致。PI计划将这一新理论的特征嵌入到PI在其早期工作中开发的职业选择动态一般均衡模型中，以定量评估不同经济力量（如学习，职业生产力或需求的波动，以及在不同职业中寻找工作的摩擦）对数据中观察到的职业流动性的贡献。该项目的智力价值在于：(1)发现了一组新的事实，这些事实表征了职业流动性的模式；(2)一种创新的研究策略，将职业流动性作为工人在当前职业中的相对表现的函数来研究；(3)发展了一种新的职业流动性理论，这种理论非常容易处理，但与它所要解释的数据的所有特征一致。(4)发展和评估职业流动的定量模型，以便更好地定量评估推动职业流动的力量。该项目将对经济学专业产生广泛的影响，因为它将(1)为区分各种职业流动理论提供重要的新经验证据，(2)提供与激励证据定性一致的职业流动新理论模型，(3)开发和校准新的工人流动定量模型。它还可能指导我们理解工资随职业经验增长的原因。现有的许多文献将这种增长归因于选择：职业匹配不好的工人离开他们的职业，在其他地方找到更好的机会，这在工人的横截面中引起了职业匹配质量和职业任期之间的相关性。鉴于PI的调查结果挑战了选择对工资增长的重要性，因为坏工人和好工人都会离开职业，人力资本是显而易见的剩余部分，可以解释工资与职业任期之间的正相关关系。这项研究的结果将在国内和国际会议上发表，并可能成为高级课程阅读清单的标准条目。

When a worker changes occupations (e.g., sales representative, mechanic, taxi driver) she usually changes the kind of work she performs, with potentially non-trivial loss of specific skills accumulated in the previous occupation. Nevertheless, the fraction of workers changing occupations is remarkably large - close to 20% of workers in the U.S. switch occupations in a given year. Moreover, the size of worker flows vastly exceeds the amount of reallocation needed to accomodate changes in occupational employment shares. Why do workers switch occupations so much? What are the consequences for the aggregate economy? Might there be a role for government intervention? The objective of the proposed research is to provide answers to these questions.The PI uses administrative panel data on 100% of the Danish population to document a new set of facts characterizing the patterns of occupational mobility. He finds that a worker's probability of switching occupation is U-shaped in her position in the wage distribution in her occupation. It is the workers with the highest or lowest wages in their occupations who have the highest probability of leaving the occupation. Workers with higher (lower) relative wage within their occupation tend to switch to occupations with higher (lower) average wages. Higher (lower) paid workers within their occupation tend to leave it when relative productivity of that occupation declines (rises).These previously unknown facts are not implied by existing theories of occupational mobility that mostly treat occupations as horizontally differentiated sets of tasks. The PI suggests that it might be productive to think of occupations as also forming vertical hierarchies. Workers who are unsure of their abilities learn about them by observing their output realizations. Employment opportunities in each occupation are scarce inducing competition among workers for them. Complementarities in the production function between worker's ability and productivity of an occupation induce sorting of workers into occupations according to their expected ability. The PI develops an equilibrium model of occupational choice with these features and show analytically that it is consistent with patterns of mobility described above. The PI plans to embed the features of this new theory into a dynamic general equilibrium model of occupational choice that the PI developed in his earlier work to quantitatively evaluate the contribution of different economic forces - such as learning, fluctuations in occupational productivities or demands, and search frictions in locating jobs in various occupations - to the amount of occupational mobility observed in the data.The intellectual merit of the project lies in (1) discovery of a new set of facts that characterize patterns of occupational mobility, (2) an innovative research strategy of studying occupational mobility as a function of a worker's relative performance in her current occupation, (3) a development of a new theory of occupational mobility that is very tractable, yet consistent with all the features of the data it is designed to account for, (4) a development and estimation of a quantitative model of occupational mobility that would allow better quantitative evaluation of the forces driving occupational mobility.The project will have a broad impact on the economics profession because it will (1) provide a new empirical evidence important for distinguishing between various theories of occupational mobility,(2) provide a new theoretical model of occupational mobility qualitatively consistent with the motivating evidence (3) develop and calibrate a new quantitative model of worker mobility. It will also likely guide our understanding of the reasons why wages grow with occupational experience. Much of the existing literature attributes a sizable amount of this growth to selection: workers with bad occupational matches leave their occupations for better opportunities elsewhere which induces a correlation between occupational match quality and occupational tenure in a cross-section of workers. Given that the PI's findings challenge the importance of selection for wage growth because both bad and good workers leave occupations, human capital is the obvious remainder that can account for the positive relation between wages and occupational tenure. The results of this research will be presented at national and international conferences, and are likely to become a standard entry on the reading lists in advanced courses.