Agglomeration and Hours Worked
发现集聚对工作时长的影响因职业和年龄而异：非专业人士工作时长随同职业密度增加而减少，专业人士则增加，且年轻人更敏感，尤其面对竞争时，这符合城市中勤奋者选择和集聚高生产力的解释。
This paper establishes the existence of a previously overlooked relationship between agglomeration and hours worked. Among nonprofessionals, hours worked decrease with the density of workers in the same occupation. Among professionals, the relationship is positive. This relationship is stronger for the young than for the middle-aged. Moreover, young professional hours worked are especially sensitive to the presence of rivals. The paper shows that these patterns are consistent with the selection of hard workers into cities and with the high productivity of agglomerated labor. The behavior of young professionals is also consistent with the presence of keen rivalry in larger markets, a kind of urban rat race. Copyright by the President and Fellows of Harvard College and the Massachusetts Institute of Technology.