Ron Brownstein: “Over the past 15 years, employment in the computer- and science-based industries at the forward edge of economic change has further concentrated into a handful of superstar cities, according to a sweeping new study released Monday… Just 20 large metropolitan areas now account for a clear majority of the nation’s jobs in the 13 high-productivity industries that the authors identify as the nation’s most innovative.” “This narrowing distribution of America’s most cutting edge, research-intensive industries — including pharmaceuticals, software, aerospace, data processing, and computer and communications manufacturing — has contributed to the concern in many smaller communities about being left behind in the changing economy.”