Team performances versus betting expectations so far

Submitted by Blue@LSU on November 2nd, 2022 at 3:42 PM

I saw this on r/cfb and thought it might be interesting for the gambling degenerates out there šŸ˜Š. It's a good visual of how teams have fared against the spread/expectations throughout the season.

https://twitter.com/statsowar/status/1587806514445631489

In the aggregate, Michigan is slightly above the neutral line, despite the high expectations. And they are in some pretty good company at the top, holding up well against the three SEC teams in the same vicinity.  

And look at UConn, outperforming their expectations! 

I also broke the data down by game to get a better look at how Michigan is performing relative to (betting) expectations in individual games. The data were taken from this website.

Here's UM's record against the spread (with the betting-line spread, the actual spread, and the difference):

Here's UM's record relative to the Over/Under (with the actual over/under, the total points, and the difference between the two):

We have a 4-3-1 record against the spread, but are only 1-6-1 for the over/under. The results for the over/under are a bit surprising. Throughout the season, we seem to be about -35. Is that because we are not scoring enough points or because our defense is too good at preventing the opponent's from scoring their expected number of points?

Bo Glue

November 2nd, 2022 at 3:53 PM ^

Contrary to popular belief, OSU is not in the SEC.

That said, I do think the trend of going under is more about our defense shutting teams down so well. Except for the OOC slate, where the betting lines were just ridiculous.

mGrowOld

November 2nd, 2022 at 4:00 PM ^

True Michigan betting story.  Back in the day my brother's best friend was an oral surgeon who hosted our blue lot tailgate and also bet a lot on Michigan each week.  Didnt matter the line, he bet Michigan and most years came out close to even.

But in 2005 he was WAY up.  We didnt have a great year in 2005 but he was real lucky, placing big bets on the games we covered and small bets on the games we lost.  So going into the OSU game he was up almost 200K for the year and Michigan was getting 3.5 points at home.  So he bet it all and with less than 6 minutes to go in the game we were up 21-12 only to allow an epic comeback by Troy Smith and the buckeyes and lose 25-21.  The baddest of bad beats as they scored a TD with 24 seconds to go (a FG means he still covers).

I've never been more sad for a bettor in my life.

gbdub

November 2nd, 2022 at 4:02 PM ^

I donā€™t think it makes sense to treat the ā€œunderā€ as a ā€œlossā€. After all, your opponent is supposed to contribute points as well, and the performance of ā€œunderā€ has as much to do with the defense over performing as the offense under performing. 

Given that Michigan is a team that gets a lot of homer money, doing any better than the spread is actually a pretty good achievement, and when the expectations are so high, especially so. 

That said I do think our position so far to the upper right has a lot to do with how terrible our early opponents were. 

Blue@LSU

November 2nd, 2022 at 4:06 PM ^

I donā€™t think it makes sense to treat the ā€œunderā€ as a ā€œlossā€. After all, your opponent is supposed to contribute points as well

That's true. It would probably be better to look at the SP+ predicted score. That would help differentiate whether we are scoring less than expected or the defense is holding the opponent to fewer points than expected.

LeCheezus

November 2nd, 2022 at 4:09 PM ^

First, ā€œthe spreadā€ is arbitrary because it can vary book to book.  I tried to figure out where they got their data but everything I clicked on tried to sell me a subscription so I gave up.  Relative to the O/U, just a few half points here and there evens the results out.

Second, almost all big variance you see relative to teamsā€™ performance against the spread in football is due to very small sample size.  Given enough data, most teams will gravitate pretty close to .500 ATS.  There can be trends (MSU has a fantastic record covering as an underdog against UM for example) where either bookmakers get it wrong or heavy betting  on one side ends up creating a line that is more about the bettorā€™s opinions than the bookmakers. 

Generally, I wouldnā€™t evaluate a team based on how they perform relative to betting lines.  No, not even for betting.  Most betting sites will openly share info like this with you right on the page where you place wagers, which pretty much proves it wonā€™t help you.

J. Redux

November 2nd, 2022 at 4:25 PM ^

Except -- they don't do that.  I mean, they'd be happy to do that, but that's not actually how it works. They don't know where the 50/50 split would land.  There's a reason that the spread is usually very close to the SP+ number; the predictive systems are a big input for the linesmakers.  (And, maybe less so for college, but for the NFL, the closing Vegas line is one of the best predictors of the final margin that you'll find).

Let's say that SP+ comes in with UM +7 in Columbus.  Now, let's say that every Michigan fan in the country starts taking bets at +7.  They might move the line to +6.5 or +6 to try to get more OSU money, but they won't move it much further than that.  If they move it too far, they risk sharps coming in and putting them way out of balance the other way.  Further, they open themselves up to being middled. Let's say that so much money comes in on Michigan that they swing to being a 7 point favorite -- nobody at all is betting on OSU.  (Maybe they heard it was going to snow, or it's flu season).  Now, people who took UM +7 are going to come back and take OSU +7.  The house just got middled -- the bettor can't possibly lose both of those bets, and is quite likely to win them both (any result closer than one touchdown wins both).

LeCheezus

November 2nd, 2022 at 4:26 PM ^

There is some truth to this but itā€™s not as simple as balancing x dollars on M +22.5 and MSU -22.5.
 

In this day and age, Oddsmakers do not get equal money on each side of every market.  If the main line is 7.5 for a football game, most books (mobile ones, anyway) will have markets at least 10 points in either direction, with odds adjusted and increasing vig the further you get from the mainline.  There is no way to balance all 20 of these markets against their opposite (ex -9.5/+9.5) for every game, so they use algorithms that take all money wagered and probabilities to create some kind of balance.  
 

In our 7.5 mainline example, if I put a ton of money on +10.5, it could move the mainline, or move it to a -105/-115 split instead of -110/-110, or shift all 20 other markets to help balance the money, even if I didnā€™t actually bet the mainline. 

BTB grad

November 2nd, 2022 at 4:32 PM ^

This is false. OSU was getting 95% of the money against U-M last year at a line of -8. Even so, Vegas actually moved the line against OSU down to -7.5 and -7 by kickoff. They likely had pro gamblers/sharps they respect (this is why lines move, not because the house is trying to get 50/50 split on money) who came in with U-M bets and had a feeling themselves that Michigan was going to cover. Basically they made a fuck ton of profit off the UM-OSU game. Vegas wants to maximize their profit, they donā€™t care about taking 50/50. Most games have a public favorite and public dog so the money hardly lands at 50/50. If Vegas thinks like they have a strong feel on a game, theyā€™ll lean into to take money out of Joe Publicā€™s hands.

https://www.espn.com/college-football/story/_/id/32721401/betting-line-moves-underdog-michigan-heavy-betting-ohio-state-ahead-saturday-college-football-game

 

Durham Blue

November 2nd, 2022 at 5:24 PM ^

I know I didn't push on my Mich-MSU bet.  The spread at game time was 22.5 so the differential there is -0.5.  The half point is a real bummer sometimes, especially in a game that we should've won by considerably more than 22 points.

EDIT: just saw the post directly above mine.  Same info...

Bo Glue

November 3rd, 2022 at 6:38 AM ^

I think Illinois might be farthest above the line. That's nice to see.

Unfortunate that our OOC trio are all far enough to the left to be easy to pick out.