The Effect of High-Tech Clusters on the Productivity of Top Inventors
研究发现，美国顶尖发明者集中在少数城市，当发明者迁往同领域发明者密集的城市时，其专利数量和质量显著提升，表明地理集聚带来生产率外部性，促进整体创新。
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.