WORK HISTORIES AND LIFETIME UNEMPLOYMENT
利用美国数据中工人终身失业的差异，发现工作分离率的差异从一开始就很大，而工作找到率的差异随职业生涯增大；构建一个对称未观测异质性的定向搜索模型来解释这些发现。
Abstract A long‐standing question in economics is how important unobserved differences across workers are for explaining unemployment. I revisit this topic using variation in lifetime unemployment across workers in U.S. data. A comparison of workers often unemployed with the rest shows that although differences in job‐finding rates increase over the course of a career, differences in job‐separation rates are large right from the start. I develop a directed search model with symmetric unobserved heterogeneity, in which agents learn workers' types from their labor market histories, to rationalize these findings. The model cannot match the data if unobserved heterogeneity is neglected.