Frictional Unemployment and the Role of Industrial Diversity
论证城市产业多样性越高，摩擦性失业率越低，基于91个大都市区的数据，最多样与最单一城市失业率差约2.4个百分点。
Since many individuals are immobile between city labor markets in the short run, the industrial structure of cities plays an important role in determining the national rate of unemployment. This paper argues that a city's frictional unemployment rate will be lower, the more industrially diversified is the city; that is, the more evenly distributed is employment across industries. The empirical work on 91 large SMSAs strongly supports the hypothesis. The difference in frictional unemployment rates between the twenty most and least diverse cities is estimated at about 2.4 percentage points.