The opening line is the first line created by the oddsmakers, which is then sent out to sportsbooks. Of course there is an entire method to the madness on how the opening line is created. Football bookmaker explained that it all starts with each oddsmaker creating a line on each game based upon their own personal approach. This usually includes having up-to-date power ratings on each team.
Power ratings are the oddsmaker`s value of each team and are used as a guide to calculate a "preliminary" pointspread on an upcoming game. The power ratings are adjusted after each game a team plays. Examples of non-game factors that would require an adjustment to a team`s power rating are key player injuries and player trades.
Once a game`s power rating based pointspread is determined, the oddsmaker will make adjustments to that line after considering each team`s most recent games played and previous games played against that opponent. Also, adjustments are made after reading each team`s local newspapers to get a sense of what the coaches & players are thinking going into the game.
Since the oddsmaker`s ultimate goal is equally dividing the betting action, public perception and betting patterns must be taken into account. For example, the public might have heavy betting interest week after week on a popular college football team such as New England Patriots. If an oddsmaker comes up with a preliminary line of New England Patriots -7, then an adjustment up to -7.5 or -8 would be made in response to the public`s expected New England Patriots bias.
The last step in the line-making process for each oddsmaker is taking one final look to determine whether or not the line "feels right." This is where common sense and past experience with how games are bet enters into the picture.
A round-table discussion among the 4-5 oddsmakers involved in making the line for each sport is then conducted and a consensus line is decided upon by the Odds Director before it is released to the sportsbooks. Of the 4-5 oddsmakers, generally the 2 most respected opinions are weighed more heavily by the Odds Director before he decides on the final line.
Why the Line Changes
Once the opening line is released by LVSC, the individual sportsbooks decide if they want to make any adjustments before offering it to the public. Reasons for such adjustments include:
Experts working for the individual books having a strong opinion on the game.
Individual books having players who consistently bet with certain tendencies (such as an extreme bias toward favorites or towad certain popular team like New England Patriots)
The purpose of these adjustments, like all line adjustments, is to more equally divide the betting action.
Once betting begins, sportsbooks can adjust the line at any time. In doing so they attempt to make more attractive the team that is getting less action. By moving the line, sportsbooks can influence how the public bets on a particular game.
For example, if the pointspread on a game is 7 and most of the money is coming in on the underdog (taking the +7), sportsbooks will then move the number down to 6 ½ to try and attract money on the favorite. Moving the line is the oddsmaker`s effort to balance betting action, and often times such moves can have a major impact on a bettor`s decision.
Oddsmakers can also change the line depending on various event-related factors such as player injuries or weather. Obviously, if the line comes out a week ahead of the event (which is the case in football), there is much that could happen during the week leading up to the event that could affect the line. Oddsmakers have to determine if any changes are necessary and send out an "adjusted line."
