A paper from Edward L. Glaeser and Albert Saiz
The authors claim that ‘For more than a century, educated cities have grown more quickly than comparable cities with less human capital. This fact survives a battery of other control variables, metropolitan area fixed effects and tests for reverse causality. [They] also find that skilled cities are growing because they are becoming more economically productive (relative to less skilled cities), not because these cities are becoming more attractive places to live. Most surprisingly, [they] find evidence suggesting that the skills-city growth connection occurs mainly in declining areas and occurs in large part because skilled cities are better at adapting to economic shocks.’
Source: National Bureau for Economic Research
http://papers.nber.org/papers/W10191