Link: http://www.boston.com/news/globe/ideas/articles/2006/03/19/ballpark_figures/

....is that sports teams seldom bring economic benefits to a city sufficient to offset all of the obvious (and sometimes hidden) subsidies paid to the team owners. This report from the Boston Globe asks when this reality is known, why are cities still falling over themselves to throw money at sports franchises?
One of the statements in the article is interesting, if only as the starting point for a question:

Less than two weeks ago, Washington, D.C., agreed to pay an unprecedented $611 million to build the Washington Nationals a baseball stadium.

This is very interesting when you consider that the estimated value of the Washington Nationals franchise is only $450m (and that is supposedly only because they will play in Washington - if they played elsewhere the value is alleged to be as low as $250m). So...if you believe that valuation, D.C. just agreed to spend nearly 150% of the value of the franchise in subsidies...or...the $450m is a lowball figure. Either way, something smells in that deal.
This is merely another example of cities being persuaded to stump up massive subsidies without any real proof of any long-term benefit.
I am watching this play out locally in Arlington, Texas. Having been played once like a fiddle in the 1990's by the Texas Rangers, who extracted hundreds of millions in subsidies from the city to build the Ballpark at Arlington, they have just been played again by Jerry Jones of the Dallas Cowboys, who persuaded the city voters to approve a massive financial incentive package so that the Cowboys can move to Arlington from Texas Stadium, which, although built in the mid-1970's, is now considered to be obsolete (for "obsolete" read "not enough high-dollar corporate suites").
The voting result might conceivably have something to do with the fact that the Cowboys apparently spent many millions of dollars on advertising and the wheeling in of various sports celebrities, whereas the opponents' budgets barely scraped into the tens of thousands of dollars. Also included in the package (wait for this) is a financial instrument described at the time as "The NFL is giving the Cowboys a $100 million dollar loan that they don't have to pay back". (Gee, I want to know where I can get one of those loans. Sign me up!). This article in Reason magazine explains how the whole deal was rapidly assembled in part to allow the (until recently) favorable attitude towards Eminent Domain to be used to remove recalcitrant property owners. The City of Arlington is already pulling out all the stops to remove these, er, um, inconvenient folks so that the construction equipment can move in to start creating the new stadium.
As a resident of Irving, I am pleased that the Cowboys are moving to another local city. That city can then find out what Irving has known for a long time; visitors to most sports stadia do not linger in local restaurants, bars, arts districts and shopping malls before and after the game. Instead, they drive into the stadium car park "moat" area, go inside, watch the game (fuelled by food and drink and concession sales, the profits of which go almost entirely to the team), then pile back into their vehicles and disappear off to their home locale. Next to no money is spent in the local districts. The much-touted "pull through" revenue effect cannot work in practice because the design and location of most sports stadia (next to intersections, with massive surrounding parking areas), makes it all too easy for spectators to both get there quickly and leave quickly without setting foot anywhere in the city except in the stadium car park.