"We know more and more of our graduates have started to stay," said Melissa Withers, spokeswoman for the Rhode Island Economic Development Corp., rattling off the names of Brown University alums who have taken advantage of tax credits to set up their businesses in Providence.

She says social networking events, like the monthly meeting of "Providence Geeks" for young tech employees, regularly bring together 200 people or more. And her job, which includes work at "The Innovation Factory," a center that works with Providence colleges, has recently gotten a lot busier.

"But that's all anecdotal," Withers said. "The best we've learned so far is that you can't over-engineer this sort of thing. You have to let some of it happen naturally."

Rhode Island plans to look at statistical data behind its effort, Withers said, but only after a few years of working on the issue.