"...Patents are the conventional measure of innovation. Despite their
various weaknesses, patents represent a systematic, quantitative measure of
innovation and are used by economists as the single dominant measure of
innovation. But, as with other measures, economists tend to measure them on
a per capita basis.
*Innovation Density: *Our measure of innovation density is patents per
square kilometer. The map below shows the density of innovation based on
this measure. The median density of innovation is .008 patents per square
kilometer. The densest metros have more than .4 patents per square
kilometer, while the least dense have fewer than .001...."
Wonder whether the results would have been any different if the investigator
had looked at Patents and European-closet density !!