Are urban labour markets more dynamic? Vacancies and urban scaling
研究发现城市中职位空缺数量相对于就业规模呈超线性增长，且技能要求越高集中度越强，这有助于解释城市中工人流动性更高和匹配质量更优的现象。
This paper shows that there is superlinear scaling of vacancies with employment size. That is, there are disproportionally more vacancies relative to employment in urban areas, not just for overall employment, but also for occupational and educational classes. Hence vacancies are more strongly concentrated than the jobs to which they refer. Moreover, we find that, compared to all employment, the concentration of labour demand increases with required skill levels. We show that the stronger growth of jobs in cities is unable to explain this finding and propose an alternative explanation based on vacancy chains in spatially related labour markets. The results suggest that on-the-job searchers have better possibilities in cities to improve their position. This helps explain the higher mobility of especially younger workers in cities and the superior quality of job-worker matches in large labour markets.