From today's Wall Street Journal:
Yes, stadiums do create high-paying construction jobs for a year or two. But the vast majority of long-term employment is low-wage concession jobs. A Congressional Research Service study of the Baltimore Ravens stadium found that each job created cost the state $127,000. By comparison, Maryland's Sunny Day Fund created jobs for about $6,000 each.
FWIW, I found no appreciable effect on St. Louis construction employment when they built the Dome and their hockey arena in a study published several years ago in the Journal of Urban Affairs. I argued that sports facility construction crowded out other building activities.
A few other paragraphs
"Walk a few blocks away from the stadiums and you'll see the net economic impact of both the Ravens' stadium and Camden Yards," said Neil deMause, author of "Field of Schemes," a book and Web site devoted to the false promises of publicly financed sports stadiums. "Both have produced a plethora of pawn shops and dollar stores." A 1998 report by the New York City Independent Budget Office found no "economic rationale for assuming that building any new stadium would itself spur construction of office towers and hotels. Total output resulting from the presence of the teams in the city amounts to less than one tenth of one percent of the economic activity in New York City."
Even the economic impact of the team's highest-paid employees, the ballplayers, is sometimes muted. Many have off-season homes in another city, where they pay taxes on their millions. And cities like Cleveland have sued to force visiting athletes pay local income taxes.
Then there's the fact that only a sliver of the tax base really benefits from a sports stadium. And with ticket prices rising rapidly, that group is getting much smaller.
The whole thing is worth a good read.