Recently, the University of Nebraska-Lincoln published a short (4 pages! – and one is a thank you page! ) report on the state of entrepreneurship in the United States. http://www.inc.com/news/articles/201108/new-york-tops-for-entrepreneurship.html
The report measured five variables to which they assigned an index value of 1.00, and measured a statistical variation from 1.00 to rank the states.
The five variables were
1) percent growth in new establishments
2) percent growth in new establishments per capita
3) business formation rate
4) patents per thousand residents
5) gross receipts of sole proprietorships and partnerships per capita