Tekhne challenge: Help Brad Feld calculate ‘entrepreneurial density’

Boulder Open Coffee Club. Andrew Hyde, Flickr

How many entrepreneurs can dance on the head of a pin? Brad Feld revisits this intriguing idea in a new blog post today.

Feld writes at Feld Thoughts to recap a post first published Aug. 23, 2010:

When asked why Boulder is such a vibrant entrepreneurial community, I talk about a concept I call entrepreneurial density.

Boulder is a small town – the city itself is only 100,000 people. Yet the number of entrepreneurs in Boulder is significant. And the number of people working for startups is off the charts. Start with the definition:

entrepreneurial density = ((# entrepreneurs + # people working for startups or high growth companies)) / adult population

My guess is that Boulder’s entrepreneurial density is one of the highest in the United States. I don’t have any empirical data to back this up – it’s a qualitative assessment based on my experience traveling around and investing in different parts of the US.

Pete Warden gave it the ol’ college try in quantifying and geo-mapping the results of a Crunchbase and U.S. Census analysis of entrepreneurial density. But, even he admits, the process was “crude.”

So Tekhne readers, let’s crowdsource this problem.

First, how would you approach Feld’s question?
Second, what’s the best data set(s) to geographically quantify entrepreneurial density?
Third, do heat maps offer the best presentation method? What about tracking over time and space?