中文摘要
高科技部门集中于少数城市。计算机科学、半导体和生物学领域最大的十个集群分别占全美所有发明者的69%、77%和59%。利用109,846名发明者的纵向数据，我发现地理集聚带来了统计显著的生产率提升。当发明者搬迁至同一领域内拥有大型发明者集群的城市时，其产出专利的数量和质量均出现大幅增加。统计显著的生产率外部性的存在意味着，发明者的集聚为美国整体创新产出的提升带来了巨大收益。(JEL D62, J24, L60, O31, O34, R32)
Abstract
The high-tech sector is concentrated in a small number of cities. The ten largest clusters in computer science, semiconductors, and biology account for 69 percent, 77 percent, and 59 percent of all US inventors, respectively. Using longitudinal data on 109,846 inventors, I find that geographical agglomeration results in significant productivity gains. When an inventor moves to a city with a large cluster of inventors in the same field, she experiences a sizable increase in the number and quality of patents produced. The presence of significant productivity externalities implies that the agglomeration of inventors generates large gains in the aggregate amount of innovation produced in the United States. (JEL D62, J24, L60, O31, 034, R32)