You can get an idea by asking whether the Olympics boosted Sydney's economy.
At Odd Numbers, Zubin Jelveh presents a persuasive answer.
Try his "spot the boost" test for yourself.
What was the name of that consulting firm that produced the impressive-looking study arguing that it would boost Sydney's economy?
Oh yes, KPMG.
The NSW Treasury predicted an even greater boost!
See also: Sunday dollars+sense: This'll be worth millions!