No, this is not a duplicate article. I wrote a similar piece that explored teams moving from 3-point favorites to 2.5-point favorites. This time, I will explore a line shift in the other direction.
Does this story describe you?
There is a close contest between two division rivals and you predict the home team to win in a close contest. The opening line gives the home team a -3 spread. You like these odds and plan to bet the game.
You wait to bet the line, thinking that it might shift down to -2.5, but the opposite happens. The line moves to -3.5 and this favorite that you were high on no longer appeals to you.
You reason that -3 was a safe line. 3-point wins are common in the NFL and this would result in a push for you. A -3.5 line turns the common 3-point win for the home team into a loss for you and this turns you off. With a field-goal victory now meaning you lose, you decide not to bet the game.
You even looked at some numbers to back you up. You found that over the past 4 NFL seasons 22.6% of games have ended with 3-point margins or closer. You deem this too risky, and feel justified in not betting the game.
You are right to not bet this game, but your logic is off. You, my friend, are falling for the spread storyline. What does this mean? I’ll explain it through the use of statistics.
Comparing Favorites at -3 to -3.5
This chart shows the ATS records of favorites since 2012 when the line is -3.
|Year||Record ATS||ATS Win %|
3-point favorites have not fared well in recent years. 46.7% is not good by any means. If moving from -3 to -3.5 is that bad, we should expect our 3.5-point favorites to have an even worse ATS record over this stretch.
This chart shows how the 3.5-point favorites have done ATS, also since 2012.
|Year||Record ATS||ATS Win %|
What’s this?! 3.5-point favorites have won 3.6% more games ATS than 3-point favorites. How can this be?
I’ll tell you why: There is no evidence that suggests a line moving from -3 to -3.5 affects a team’s chances of covering … none.
Check out the numbers. So far this year, 3.5-point favorites are winning at a lower rate ATS than 3-point favorites, like we’d expect. There is no consistency or trend to this data, however.
Last year, 3.5-point favorites won way more frequently ATS, while 3-point favorites were better in both 2015 and 2016. In 2012 and 2013, 3.5-point favorites killed it, blowing 3-point faves out of the water.
If 3.5-point favorites are not consistently worse than 3-point favorites, there is no excuse for being scared to bet them.
Why then do bettors routinely let very small line shifts affect their perceived odds of winning a bet? Here is why: there was never confidence in the bet to begin with. If moving from -3 to -3.5 discourages us from a betting a favorite, we probably were not too high on them to begin with.
Vegas is a buzzsaw. To profit from sports betting, you cannot afford to be making poor bets. Backing a team you are not uber-confident in will give up any edge you once had on the experts.
The next time you are thinking of placing money down on a 3-point favorite, think if you would make the same bet if the line was -3.5 Remember, 3.5-point favorites have won 3.6% more games ATS since 2012 than 3-point favorites.
Stay smart out there!
Kreighton loves sports, math, writing, and winning — he combines all of them as a writer for WagerBop. His favorite sports to review and bet are MLB, NFL, NBA, NCAAF, and NCAABB.