The eureka moment happened when he saw numbers compiled by one of his doctoral students, Gary J. Gates, on concentrations of gay and lesbian people living in metropolitan areas - numbers published with another author last May in Demography, a peer-reviewed journal of the Population Association of America.
Florida took Gates' rankings of areas. He compared them with the Milken Institute's "Tech-Pole" rankings of high-tech presence in metropolitan areas. He discovered, to his surprise, that the number one thing that correlates with a region's high-tech success is the concentration of gay people living there.
Close behind were concentrations of people with college degrees and people who fit into the Carnegie Mellon researchers' Bohemian index - people who identify themselves to the U.S. Census as artists, craftspersons and musicians.
But gay concentration led the list.
Could that be right? Could there be a connection between gays and high-tech success?
To be sure, the theory has its skeptics. Some regional-economic-growth analysts are deeply dubious of any cause-and-effect inference.
"High tech in Washington is a function of federal spending," says Stephen S. Fuller, of the School of Public Policy at George Mason University. "Federal purchases of technology services and products have grown from $900 million in 1980 to $14 billion in 1999. That's a pretty big inducement to come here. The biggest motivation for migration is economic opportunity."
Nonetheless, he acknowledges that there has been "a cultural transformation that goes with economic transformation. That has really been stark in the last 20 years. The Washington area during the '80s was the second-fastest-growing in the country after Los Angeles. There was a huge diversification of the population base. The new economy has been tied to new cultures and populations."
Robert Ady, former president of Deloitte & Touche/Fantus Consulting, who is credited with guiding more business relocations than any other person, says "the real driver has always been the availability of a qualified workforce. Nothing else comes close."
The picture starts out fuzzy.
For instance, Florida and Gates can't get their numbers down to small neighborhoods, only entire metropolitan areas. Neither can they tell how gay any illustrious high-tech area might be.
What they can say is that the San Francisco Bay area ranks first in both gay and high-tech categories, according to census figures and the Tech-Pole ratings generated by Milken, a new-economy think tank.
Milken measures the concentration of gay people living in an area by those who say they are living with their "unmarried partner" of the same sex. To determine a high-tech region, the Milken method combines two measures: a region's portion of the nation's high-tech output, and how many high-tech industries are concentrated there.
So what's to be made of the Carnegie Mellon work?
One possibility is that the numbers are just wrong. But that seems unlikely. Both the gay and tech lists sound right, says Megan Smith, chief executive officer of PlanetOut.com, an Internet media company for gay men, lesbians, bisexuals and transsexuals.
"That's a good list. If we look at our member data, these cities skew," she says.
Meanwhile, the Milken Institute also publishes a list of fast-growing new places for business and career. In the 1999 list, the three hottest - Atlanta, San Diego and Austin, Texas - were places that right now rank higher as gay cities than as tech cities. Could that mean that being a gay place predicts the future success of a tech hub?
"That's an intriguing question - whether it is a leading indicator," says Ross DeVol, the director of regional and demographic studies at Milken. "Anecdotally, it seems to fit pretty well."
So the numbers remain stubborn things. They demand explanation.
Perhaps the connection between gays and high technology is as Florida and Gates suspect: We're looking at places comparable to 17th-century Amsterdam at the time of Rembrandt and mercantilism, places that have figured out a way to translate open-mindedness and tolerance into economic dominance.
"Our argument is that this captures a diversity of thought," says Gates, who is now with the Population Studies Center of the Urban Institute in Washington. "You would expect that places that are welcoming to gays would be welcoming to other people who are different. It's a measure of a kind of tolerance that's appealing to the high-tech industry."
Robert Yaro is executive director of the Regional Plan Association in New York, the nation's oldest civic planning organization. Like Florida, he has noticed that Carnegie Mellon has been "banging out these top-quality Ph.D.s, and six out of 10 end up in Boston, New York, San Francisco, Seattle. Why didn't they stay?" (Pittsburgh ranks 39th on the gay-concentration list and 25th on the tech list.)
Says Yaro: "The places they're moving to are the most unbelievably open and tolerant places on Earth. . . . They are academic centers that are drawing from all over the world."
In areas such as Washington, at least, there's anecdotal support for the proposition that high tech and gay show considerable overlap.
"Well, of course tech is gay," says an engineer at a gay techies social event in Reston, Va. "Who do you think was messing around in the middle of the night with all those mainframes way back when? People like me who couldn't get a date, back when I was straight."
"We don't have families, so we can stay late," says another man. "You can travel at the drop of a hat if you have no partner," says another.
Gay males are sometimes capable of buying high quality of life, Gates notes. Two men are likely on average to make more money than a couple made up of a man and a woman. At the same time, a couple without children probably has more discretionary income than one with children.
"Because they are so focused on finding great talent, tech companies are more flexible," says PlanetOut's Smith. "Whether it means pinball machines in the office, or working at 4 in the morning, or hiring a single parent, or a gay, they're looking to create a welcoming environment for a huge range of people. At IBM the corporate mantra is 'None of us is as strong as all of us.' That's such a tech thing. As long as people are effectively working as a team, people would really care less what they are doing at home."