Oh, Crap Comment Count

Brian

So a few months ago Chris Stassen, maintainer of the invaluable Stassen.com, emailed me to note that his name was not, in fact, "Harold." I had been calling him Harold for years.

Oops.

So I don't know if this is revenge or whatever, but yesterday this hit my inbox from Mr. Stassen. It's possibly the most frightening thing I've ever seen. The elderly, children, and pregnant women are advised to stop reading now.

I warned you…

Last year I stumbled across a research paper on the odds of a Vegas favorite winning a game (e.g., a 1-point favorite wins 53% of the time, a 7-point favorite wins 69% of the time).  The research was based on Vegas lines and NFL games, so one can argue against applying it to the college game.  I think college teams perform less consistently than pro teams (meaning that a big NCAA favorite is less guaranteed to win than an equivalently big NFL favorite)... but probably it gives a decent rough measure.

The other problem I've had is how to get "lines" for games which are purely only hypothetical (e.g., Texas Tech vs Kansas in the Big XII title game), or games which are weeks away and not big enough for Vegas to publish an early line (e.g., Michigan at Purdue).  I've finessed this issue by using Sagarin's PREDICTOR ratings (his best estimate of team strength) to compute spreads.  Again, this sort of abuses the research paper's results, in that his spreads aren't the same as Vegas lines (though they tend to be pretty similar).  Anyway, if we're only looking for ballpark figures, we don't have a lot of other options if we want to do this sort of computation.

There are lots of various ways to throw rocks at this analysis.  I did a similar one for Ohio State fans at the start of the season, and computed that Ohio State was twice as likely to lose 3+ games, as they were to go undefeated.  That was not too popular with the OSU fanbase, but I think I will be somewhat vindicated by the end of the season.

Anyway, even though there are weaknesses, I think the analysis' results are useful for looking at how a season "should" play out.  More important than the spreads and exact per-game probabilities going in, are the ways in which the probabilities of individual games combine into the probability for this or that overall record.

Without further ado, here's the result for the remainder of Michigan's season:

By Sagarin-predictor pointspreads, Michigan is an underdog of more than a touchdown in every remaining game:

+8 at Purdue,
+9 against Northwestern,
+15 against Michigan State,
+16 at Minnesota,
+21 at Ohio State, and
+34 at Penn State

Using these numbers, the composite odds for Michigan's final six games of the regular season are:

6 wins =  0.0% (8-4)
5 wins =  0.0% (7-5)
4 wins =  0.4% (6-6)
3 wins =  3.9% (5-7)
2 wins = 18.7% (4-8)
1 wins = 41.8% (3-9)
0 wins = 35.2% (2-10)

By that calculation, Michigan is more than 75% likely to finish either 3-9 (one win in their remaining games) or 2-10 (no wins), with 3-9 being a bit more likely than 2-10.

They're a 22-to-1 longshot to exceed 4-8, and about a 250-to-1 longshot to be marginally bowl eligible at 6-6.

Individual results [excised for space and horror considerations; it's just the numbers in detail]

The most likely single outcomes are:

(1) Lose all remaining games (35%)
(2) Beat only Purdue (14%)
(3) Beat only Northwestern (12%)
(4) Beat only Michigan State (6%)
(5) Beat only Minnesota (6%)
(6) Beat Purdue and Northwestern (5%)

-------------

Anyone still alive after all that? If so: computer ranking are pretty crappy measures of team strength even at the end of the year, and they can be wildly inaccurate with only six games of data. The thing that jumps out at me is the Penn State spread, which is a full ten points higher than the Vegas line. FWIW, the Vegas line is always a more accurate predictor than computer rankings. This is considerably more grim than the facts on the ground. Probably.

But… yeah. I'm building a bomb shelter.

Comments

Brian

October 15th, 2008 at 3:22 PM ^

You are correct, but this is also correct: the Vegas line has been a better predictor of outcomes than any computer attempt ever. So if the line is more optimistic than PREDICTOR, that's good news for us.

Of course, optimistic is relative here.

Anonymous Coward (not verified)

October 17th, 2008 at 10:54 AM ^

Brian,

 The standard deviation for NCAA is significantly higher than NFL. In college football, large upsets (see Toledo), and large variances from predicted score (Illinois) happen relatively frequently. In the NFL (probably due to large gambled amounts, and thus, more accurate lines) huge upsets are very, very rare.

That being said, I'd love to get a copy of that paper and I'll happily take the points in the rest of Michigan's games this year.

Matt Wilk

matty blue

October 15th, 2008 at 2:23 PM ^

i always thought it was funny that stassen's name was "harold."

 

harold stassen was the punchline for one of my favorite doonesbury cartoons, once i looked him up (this was pre-internet, i'll point out).  the guys are playing poker, and one says "my hand has the strength and determination of robert mcnamara."  the next says "mine has the charisma of ted kennedy."  after a beat, mike mumbles "harold stassen."  or some such - turns out that stassen was a perennial losing presidential candidate, sorta like ralph nader or dennis kucinich.  i seem to recall a simpsons reference, too, but i can't remember what it was.

 

the point?  too bad it's NOT harold stassen, maybe we could disregard the numbers. 

Anonymous Coward (not verified)

October 15th, 2008 at 2:52 PM ^

Future games arent independent events, if they were the lines wouldnt change after a game.  the mean is still accurate but your tails are way too thin.

Anonymous Coward (not verified)

October 15th, 2008 at 4:02 PM ^

Sagarin's PREDICTOR ratings are distinctly biased towards high scoring (fast paced) teams,  because he uses a 1D game-output function (using only the point differential), and, of course, fast-paced teams create a larger point differential even though the game's not that much more winnable. I liked Massey's "power" ratings better (he uses a 2D GOF), but they're gone now, unfortunately.

Sigh. Someone really needs to come up with a college-football rating that's intended to be predictive, rather than descriptive (which is what you need for the BCS) and is *transparent*, so people can criticize it. 

Anonymous Coward (not verified)

October 15th, 2008 at 5:41 PM ^

But soon as UM beats somebody those point spreads change.  Just beating Purdue would probably put the Northwestern game at less than a TD.  Beating little bro would make big changes.  I still think we win at least 2 more.

Don

October 15th, 2008 at 6:16 PM ^

give up their tix in frustration this year, then all this pain will have been worth it.

One random fact I unearthed yesterday is that in all the years we've been playing MSU, Sparty has never once scored as many as 40 points on us. If that's going to happen any year, it will be this one. Not sure I'd bet on that, though.

Ernis

October 16th, 2008 at 9:19 AM ^

Didn't Vegas also give us the 10th best odds to make it to the national title game this year?

There is one source of hope: intangibles. In college football, anything can happen. I am still confident we can win out (except probably against PSU... but whatever). If you could just go by the numbers, USC would be undefeated every year. I think it would help if someone sent this research to the team... it would motivate the hell out of me in their situation.

Speaking of intangibles don't forget that -- hard as it may be to believe during this season -- the players may have completely overlooked Toledo (it's happened before) and forgot about the whole "Oh yeah we aren't good now" thing. I'm sure at least some of them did. So... I'm saying there's a chance...