Metropolitan areas with population densities of about 4,000 people per square mile tend to produce the highest rate of patenting, according to a recent article in the American Journal of Economics and Sociology. In a study of U.S. metro areas over a ten-year period, the authors found that metro population density has a significant positive correlation with patenting rates.

Invention is a driver of economic growth. That is the assertion of Brookings latest report on U.S. patenting and its effect on the country's economic prosperity entitled Patenting Prosperity: Invention and Economic Performance in the United States and its Metropolitan Areas. The U.S.'s innovative capacity and activity has increased steadily, but other nations are catching up and the U.S. must identify the implications of this fact to remain competitive.