Sometimes, in certain bowl games, there may be significant line movements leading up to the kickoff time for the game. Line movement simply refers to any occurrences where the opening line differs from the closing line. For example, Alabama opened as -10.0 favorites but right before game time, Alabama closed as -12.5 favorites. This indicates a presence of line movement as the opening and closing lines differed. However, even though opening and closing lines may be the same, there may still have been line movement during the period from when opening lines were released, with the only exception that lines were moved before kickoff right back to the number of the opening line.
Reason For Line Movement
Line movement occurs due to the fact that sportsbooks are trying to balance the action on each side of any given game. However, this is next to impossible as the ideal situation for any sportsbook is to have exactly 50% of the action on one side and 50% of the action on the other side.
Another theory surrounds the idea that sportsbooks move their lines in order to try and take more action on the side that they believe will be on the losing end. Essentially, these sportsbooks are betting on one of the teams by trying to force action on the other side of the bet. However, a knock against this theory is due to the fact that it makes no logical sense for a business built on profiting off the juice on bets to be taking this level of risk.
Definition Of In Favor
The definition of in favor technically means the opposite of what it should. If a team opens as -10.0 favorites but the line moves to -12.0, this means that the line has moved in that team’s favor, even though you’d technically be getting a worse line if you’re planning on betting on this team.
Based on the bowl games from the past two seasons, if you had bet on every team that the line appeared to be moving in favor towards, you’d end off with a .531 winning percentage, with 34 wins and 30 losses – not exactly spectacular results, but not bad nonetheless. When we break this down even further, if the line movement favors the favorite, the winning percentage becomes .563, with 18 wins and 14 losses. On the other hand, if the line movement favors the underdog, the winning percentage drops to .500, with 16 wins and 16 losses.
Breaking down all of the bowl games into another category (December vs. January), we get a winning percentage of .476 in December, with 20 wins and 22 losses, and a winning percentage of .636 in January, with 14 wins and eight losses. While more data would obviously be preferred, this may still be indicative of a more general trend.
Additionally, for line movements of half to two points, nothing stood out in particular. However, for line movements of two-and-a-half points, the team that the line moved in favor of ended up with a .769 winning percentage, albeit with 10 wins to three losses.
While we were able to derive some conclusions from the data, the dataset itself was way too limited in its applicability and as a result, we should not be heavily reliant on what the data shows us.