Wednesday, January 26, 2005

Line dance

It's remarkable that with the amount of gambling going on, so many people are still confused about what a betting line is telling them.

Almost immediately after the Patriots beat the Steelers in the AFC title game, bookmakers set an opening line of Patriots -7 against the Eagles. What this means: If you bet on the Patriots, then at the end of the game, their point total, minus 7 points, has to be greater than the Eagles' point total for you to win. (The Eagles, on the other hand, are +7 against the Pats. You take their final score, add 7, and compare it to the Patriots'.) That's pretty basic stuff. But soon after the line was posted, I heard someone -- a Pats fan, no less -- say, "Can you believe this? The Patriots are 7-point favorites already?" Actually, I could believe that. But that's not necessarily what the betting line is saying. This is what most people don't seem to understand: The purpose of the betting line is not to predict who will win a game. The purpose of the betting line is to make sure that equal numbers of people bet on each team.

On my way home from work tonight, the late shift at ESPN Radio was discussing a poll or survey in which 63% of respondents predicted the Patriots would win Super Bowl XXXIX, and 37% picked the Eagles. A bookmaker doesn't want 63% of his customers betting on one team, because if that team wins, he's going to take a bath. So he needs to shift 13% of the betting public from the Patriots to the Eagles. He does that by manipulating the betting line until the wagers are in balance.

New England has won two of the last three Super Bowls ... but only by a field goal. Bettors might be confident that Tom Brady will do whatever it takes to win. But can they be sure he'll win this one by more than 3 points? Bookmakers believe that enough gamblers have enough doubt about that that they'll put money on the Eagles -- either to win outright or to lose by less than 7 points. If the betting line sets the bar too high for the Patriots -- if too many bettors doubt that New England will win by more than a touchdown -- then the money will tilt toward the Eagles. In response, the bookmakers shift the line again until the bets are back in balance. By Super Sunday, the line could by Patriots -2. Or the Eagles could be -2. Did Brady suddenly get 5 points worse? Did Philly get 9 points better? No. Outside events -- say, T.O.'s busted paw -- can sway the line, but for the most part, it just moves with the market. That's what more people should understand.

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