"The Effect of  High Tech Clusters on the Productivity of Top Inventors" Abstract: The high tech sector is geographically  concentrated in a small number of expensive cities. The degree of geographical clustering by research field is very high, with the top ten cities in  "Computer Science", "Semiconductors" and "Biology and Chemistry",  accounting for 70%, 79% and 59% of inventors in their field, respectively.  These shares have been growing since  1971, indicating increased agglomeration. Why do high tech inventors tend to…