Agglomeration of Invention in the Bay Area: Not Just ICT
研究发现美国湾区专利占比从1976年的4%升至2008年的16%，部分由信息通信技术驱动，但非ICT专利占比也显著增加，表明发明活动跨技术领域的共同集聚趋势。
We document that the Bay Area rose from 4% of all successful US patent applications in 1976 to 16% in 2008. This is partly driven by the increase in the prevalence of information and communication technology; however, even for patents unrelated to information and communication technology, we see a disproportionate increase in the share of US patents from the Bay Area. We interpret this growth as a trend to coagglomeration in invention across technologies, and explore different dimensions of this trend.