Now that we understand some of the mechanics of betting the point spread and why the line moves, there is a question that comes up regularly about the genesis of the line.
Who sets the line and how do they set it the damn thing?
The first line, also known as an ‘overnight line’ or ‘opening line’ is an educated guess, often by the smart sportsbook guys in Las Vegas or with online sportsbooks. [ See opening lines for each game by clicking on the league navigation links at the top of the page. ]
Oddsmakers have forgotten more about the teams in the past five minutes than most of us can ever learn in a lifetime. They are clever and know their stuff. They also know about the public perception of each team and about all the stats, both the important ones and the meaningless ones.
They know people in Boston will bet the Patriots if they are favored by 6 points or 8.5 points, so why not give themselves more of an edge? They know it's considered heresy for Texans to bet against the Cowboys, so let's open Dallas at -8, even though the 'real' line is around -6.
Oddsmakers have computer algorithms and fancy math formulas that help to generate a rough guess at the line. They use power rankings to crunch numbers and rank how the teams fare against each other in key stat categories. It’s a number they hope is right in the sweet spot where half the bettors will pick one team and half the bettors will pick the other team.
It is not their predicted margin of victory, although they sometimes come very close to it in setting their numbers.
Then, they typically offer that opening line to a select few sports bettors to see which side those professional bettors will pick. Armed with that information, and factoring in home field or home court advantages and weather or injury situations, the oddsmaker will refine the line to a point and then push it live for the public.
Now it’s available for the public to bet on, although not many jump on the first line. Some wait to see how it moves, how the betting public treat the line and then decide for themselves when – or if – to place their bet.
Sometimes the best NFL line is the first one you see on Monday morning. Sometimes, it’s five minutes before game time. If everyone starts betting on one team, that tells them their opening line may be off and they will start to move it.
If it opened at -7 for Green Bay and everyone is betting the Packers, they will move the line to -8 or -9 to encourage people to bet on the other side for the underdog Bears.
Good luck finding the best line!