Contrary to the advertising slogan, what happens in Las Vegas doesn't always stay in Las Vegas.

Rather, it shapes the world economy, the founding director of Metropolitan Institute at Virginia Tech said.

"Is Las Vegas a world city? It depends on how you define it," Robert Lang said Tuesday at a meeting of the local chapter of Urban Land Institute. "Bottom line, it's not New York or London."

Las Vegas doesn't have the scale or product services of most world cities. But for air travel and a place for businesses to convene, it's in the same class as cities such as Madrid, Spain, and Rio de Janeiro, Brazil, Lang said.

"Las Vegas is the world's largest ad hoc exchange for business information," he said. "Trade shows in the past were a dismissed category, a bunch of business guys getting drunk together. The important thing is you come face to face with people you do business with. You want to get to know somebody, you go to Las Vegas and get drunk with them."

The size and scope of some conventions make Las Vegas a world city, he said.

The International Consumer Electronics Show brings 150,000 people, National Association of Broadcasters brings 100,000 and the World of Concrete Expo brings 85,000. Even the International Wireless Communication Expo has 15,000 attendants. You miss opportunities by not being there, he said.

Room rates in Las Vegas reflect the value for access to trade shows. Lang said he used to stay at the Las Vegas Hilton for $19 a night. The last time he was here for a shopping center convention, it was $450 and $550 a night.

"Trade shows add to the region's hypergrowth," Lang said. "If you took out trade shows, would it have to be replaced? Yes, absolutely."

Las Vegas doesn't qualify as a "megapolitan" area under criteria set by the Metropolitan Institute's College of Architecture and Urban Studies, primarily having a population of 5 million by 2040. Lang said Las Vegas' metropolitan statistical area, including Mohave County, Ariz., will reach 4 million in population.

The region faces serious growth challenges and will be "dwarfed by the sun corridor." It doesn't have the water supply of Phoenix and most of the land is controlled by Washington "bureaucrats," he said. Also, the city didn't reach the threshold in the 1950s for federal funding of interstate highway development.

"One thing that happened in Las Vegas is nobody thought it would be that big," he said. "So you don't have the freeways. People were counting on Albuquerque (N.M.) and Oklahoma City."

Lang said Las Vegas should establish a better local linkage, especially to Arizona.

"Las Vegas and Phoenix are really the children of Los Angeles and there are dependencies on Los Angeles," he said. "People fly in from L.A. and do their business and take their money back home. They treat you as a branch office."

One of the advantages Las Vegas had over Los Angeles for years was cheaper costs, which it still has, but not the way it once was, Lang said. Now places such as Boise, Idaho, and Salt Lake City are getting noticed.

"A guy took me to a gay and lesbian bar in Salt Lake City and the guy was Mormon," Lang said. "I didn't know what to do in there. They were drinking, too. I don't know what's a bigger breach. Utah is getting progressive."