Vegas Knows Best: Yesterday Was Once Tomorrow
After taking last week off, this week's Vegas segment will look at preseason expectations and determine how badly "we" misjudged based on against-the-spread numbers. The conclusion will be that preseason expectations are crap, but you already knew that.
One way to judge a team against prior expectations is to look at their record against the spread. Vegas' lines aren't designed to totally split betting as is sometimes reported, but they do adjust true linesmakers' odds (ie the "true spread") if one particular school is being bet on too heavily (often the result of the general public being very high on a particular team).
First, we should review some preseason expectations in order to see where each team was pegged in August. Next to each preseason rank is the current Big Ten rank based on in-conference record. This is clearly not any type of predictor as to how they will finish because, obviously, there are more games to play. But it's what we have so far and, honestly, probably not that far off from how things will end.
| Team | Preseason Rank | Current Rank | Delta |
| Ohio State | 1 | 1.5 | -.5 |
| Wisconsin | 2 | 10 | -8 |
| Illinois | 3.5 | 6.5 | -3 |
| Penn State | 3.5 | 1.5 | +2 |
| Michigan | 5 | 8 | -3 |
| Michigan State | 6 | 3 | +3 |
| Purdue | 7 | 10 | -3 |
| Iowa | 8 | 6.5 | +1.5 |
| Northwestern | 9 | 4.5 | +4.5 |
| Indiana | 10 | 10 | 0 |
| Minnesota | 11 | 4.5 | +6.5 |
It's worth nothing that every single preseason ranking (comp chart found here, and linked in the table) had Ohio State winning the thing. Wisconsin was a popular pick for the two spot and Minnesota found itself sporting the last position in 10 of the 15 polls. Penn State was put as high as two and as low as seven.
I used a little bit of fuzzy math on the current standings. I wanted a round number of 66, the sum of the standings, and so several teams got half points. I also gave teams with more wins/losses more/less credit, which might not be fair but this isn't a research paper or the BCS standings so it shouldn't bother anyone.
So listed in order of their Delta, with two new columns: the current record against the Vegas spread and that record's winning percentage.
| Team | Delta | ATS | ATS% |
| Minnesota | 6.5 | 5-1 | 83% |
| Northwestern | 4.5 | 3-3 | 50% |
| Michigan State | 3 | 4-4 | 50% |
| Penn State | 2 | 5-1-1 | 79% |
| Iowa | 1.5 | 5-3 | 71% |
| Indiana | 0 | 0-5-1 | 8% |
| Ohio State | -.5 | 2-5 | 29% |
| Michigan | -3 | 1-6 | 14% |
| Illinois | -3 | 3-3 | 50% |
| Purdue | -3 | 2-3-1 | 42% |
| Wisconsin | -8 | 2-5 | 40% |
Now the Delta figure has some limits, of course. Teams that start close to the bottom, like Indiana and Purdue, simply don't have that far to drop. Teams with higher expectations though, like Michigan and Wisconsin, have a long fall and thus were able to pick up more points. This works in reverse too, of course.
The ATS numbers are a lot more complex. Since the spread for each game is set a week before kickoff and not all at the beginning of the year, you get evolving expectation built into them. Another thing to keep in mind is that more popular teams, namely Penn State, Ohio State and Michigan, are going to generally perform worse against the spread because of action they get for simply carrying the name. Ohio State is always going to get the benefit of the doubt, and besides, betting on Northwestern-Duke just isn't that much fun.
The three best performers ATS: Minnesota, Penn State and Iowa, represent preseason rank 11, T3 and 8, respectively. Penn State is the exception, but generally speaking picking up these pre-season basement dwellers would have been a good investment. It was highly unlikely that Minnesota, a team that returned most of their starters, was going to equal last season's abomination.
The three worst performers ATS: Indiana, Michigan, Ohio State, represent preseason rank 10, 5, and 1, respectively. Ohio State has been underperforming all year against lesser competition; always winning but never looking very impressive. The reputation of their talent, however, leads most people to think they are simply being sloppy rather than conclude that the team just isn't very good. As a result, the spread continues to be higher than the final score. Indiana and Michigan, well those two teams are terrible, there isn't much else going on there.
So the moral of the story: well for starters, the preseason rankings, even when looked at in consensus, are not very accurate. There are just too many variables. Secondly: even when accurate, the lows are not as low as they seem and the highest ranked teams are a lot more vulnerable than we are lead to believe. Ohio State, fresh off of an MNC game and returning just about all of their key players, was demolished against (an also vulnerable) USC team and will be playing the role of underdog against a team that was ranked pre-season in the late teens. While the prior season's performance and current number of returning starters matters, it's hardly a reliable way to predict future performance and appears to be incredibly overvalued by both the AP voters and the betting public.
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Comments
Lines aren't set to split the betting?
Really? I always thought they were…otherwise Vegas is essentially betting. Whereas, if the bets are split evenly between both teams, then they win the vig (10%) at no risk.
You seem to admit that lines move in response to betting…so what’s the difference? Why would Vegas not set the line to split betting, but then move the line if the betting is too heavy on one side?
I wouldn't trust old rooster me neither.
by spakajewia on Oct 21, 2008 10:27 AM EDT reply actions 0 recs
well there are different ways to look at it
The reason they don’t mind taking risk on certain games is that they know they are smarter than you. Over a large sample size then can make more money that way. I don’t claim to know a lot about it, but I can find you a link.
Kevin @ Black Shoe Diaries
by Kevin HD on Oct 21, 2008 10:33 AM EDT up reply actions 0 recs
Please
I would like a link.
I suppose, deep down, I don’t really care one way or another, but if the line seems crazy (in a bad way for PSU—not really the case so far this year), I like to hang my hat on the idea that the “experts” aren’t thinking that, it’s just where the (stupid) public is putting its money.
I wouldn't trust old rooster me neither.
by spakajewia on Oct 21, 2008 10:47 AM EDT up reply actions 0 recs
check this out
It’s long and dense but gets at the point. He has some conclusions on page none that are relevant.
Kevin @ Black Shoe Diaries
by Kevin HD on Oct 21, 2008 11:33 AM EDT up reply actions 0 recs
wow
I was completely expecting a blog post or something much less well reasoned. I’m a big fan of the Chicago school of economics—have been reading “When Genius Failed” recently, which is a great book and particularly interesting in light of the recent financial crisis—so can’t wait to read this.
thanks.
I wouldn't trust old rooster me neither.
by spakajewia on Oct 21, 2008 11:51 AM EDT up reply actions 0 recs
I'm halfway though that also.
make sure to read Liars Poker also (if you haven’t already), it’s a couple of the same guys from When Genius Failed, written by the guy who wrote Moneyball.
Kevin @ Black Shoe Diaries
by Kevin HD on Oct 21, 2008 11:53 AM EDT up reply actions 0 recs
you should check out
the blind side, which is also by that same guy. Although, given your other reads, and the fact that you write for this blog, odds are you’ve already read it.
I wouldn't trust old rooster me neither.
by spakajewia on Oct 21, 2008 3:05 PM EDT up reply actions 0 recs
The guy who has been doing the PSU Undefeated Odds
follows this logic. (Here is the pre-Michigan one)
Kevin @ Black Shoe Diaries
by Kevin HD on Oct 21, 2008 11:35 AM EDT up reply actions 0 recs
Steve Levitt is smarter than all of us.
http://www.caribsports.com/ – Click on player picks
http://www.vegasinsider.com/ – scroll down
http://www.wagerline.com/ – click on consensus picks
Books don’t take equal action. That is probably the biggest myth in the sports wagering market. You think they threw out Alabama -6.5 vs. Tennessee expecting to receive equal money? The lines have more to do with public perception which in turn can be quantified into expected value. If they wanted split action, they would know the number that would attract it. Money does indeed move lines, though.
http://sportinvestments.blogspot.com
by HolyBuckeye on Oct 21, 2008 11:49 AM EDT up reply actions 0 recs
but if the line seems crazy (in a bad way for PSU—not really the case so far this year), I like to hang my hat on the idea that the "experts" aren’t thinking that, it’s just where the (stupid) public is putting its money.
Then this week is your week to worry. Plenty of the (stupid) public is backing PSU.
Remember the opening lines are sharp. The oddsmakers most certainly know more than the rest of us. They will take on risk, but will adjust when the action they’re taking on creates too much.
by Kunk on Oct 21, 2008 11:49 AM EDT up reply actions 0 recs
For example
PSU opened as a 1.5 point favorite but has moved to 2.5 point favorites because of the betting was heavy.
JoePa in '09
by JGuiher on Oct 21, 2008 10:39 AM EDT reply actions 0 recs
Whatever Bleed Blue 'n White thinks
is what I think. I know when to defer to people smarter than me.
by Cairo on Oct 21, 2008 10:40 AM EDT reply actions 0 recs
Did you look at the current Big Ten standings before writing this post? Certainly doesn’t look like it.
by sullivti on Oct 21, 2008 3:58 PM EDT reply actions 0 recs
Yes.
This is the order I used for Big Ten standings: OSU, PSU, MSU, NW, Minn, Ill, Iowa, Pur, Wiscy, UM, Indiana
That’s the same way they are listed in the standings, although I did use a little discretion when deciding when a team was tied with another and when they weren’t. I think you might be a little confused because none of the tables list the teams in that order (the first is pre-season rank, the second is position change).
Kevin @ Black Shoe Diaries
by Kevin HD on Oct 21, 2008 4:44 PM EDT up reply actions 0 recs
Then how is Purdue (.000) above Michigan (.250), Indiana (.000), and Wisconsin (.000). Logic dictates they should be below Michigan and either tied for last with the other two, or above only those two on the basis of fewer games played.
by sullivti on Oct 21, 2008 4:52 PM EDT reply actions 0 recs
You’re right, Purdue and Michigan needed to be switched. I’ve fixed, thanks for the catch.
Kevin @ Black Shoe Diaries
by Kevin HD on Oct 21, 2008 7:16 PM EDT up reply actions 0 recs
Meanwhile, back in Las Vegas
I’d like to know how the oddsmakers figure in a head coach’s personality. The Nits sat Royster in the 4th, and ran Green into the line twice, then kicked a field goal in a spot where any other team would have gone for the TD. After the field goal the score differential was 22 points. A sure bridge-jumper. If not for the tremendous screen play the Nits missed covering.
Don’t ever bet Joe to cover.
by dr kill on Oct 21, 2008 6:28 PM EDT reply actions 0 recs
I'm positive
that the Nittany Lions are above .500 this year against the spread. The beauty of the game against Michigan was that I got to explain to my wife the term “backdoor cover.”
I wouldn't trust old rooster me neither.
by spakajewia on Oct 22, 2008 9:34 AM EDT up reply actions 0 recs
my wife is hot
I wouldn't trust old rooster me neither.
by spakajewia on Oct 22, 2008 9:34 AM EDT up reply actions 0 recs
not if she didn't already know about a backdoor cover
though now she knows we’ll see where she goes with it
by The JuggerNitt on Oct 22, 2008 11:24 AM EDT up reply actions 0 recs
I hate when hot chicks try to
cover the back door. JUST LET US TRY IT ALREADY!
I bleed Blue and White.
by Horse N Buggy on Oct 22, 2008 1:32 PM EDT up reply actions 0 recs
Did you draw any diagrams
in your explanation?
pax et amor
by jtothep on Oct 22, 2008 12:29 PM EDT up reply actions 0 recs

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