Skip to main content

Snake Eyes

One basic mathematical truth about college football that I have posted about is that the Vegas line is the best overall predictor of the outcome of games, but that the variance is actually much higher than fans think. 

For a large set of games with exactly the same line, the average margin of victory for the favored team is generally equal to the Vegas line. Furthermore, I have shown that the distribution of the margins of victory follows the Gaussian / Normal distribution with a standard deviation of almost exactly 14 points.

Practically, what this means is that only about two-thirds of all games (68.3%, to be exact) will end up with a final margin of victory within 14 points of the spread. Of the remaining one-third of all games, half (about one in six) will result in the favored team covering by more than 14 points, and the other half (one in six) will result in the favored team not covering by more than 14 points.

This past weekend, MSU was favored by 13 points and wound up losing by 11 points (a swing of -24 points, well over one standard deviation)

This past weekend, UofM was favored by 3 points and wound up winning by 25 points (a swing of +22 points, also well over one standard deviation)

In other words, MSU had an anomalously bad weekend, while simultaneously, UofM had an anomalously good weekend.

As stated above, if we just consider the odds of finishing above or below 14 points from the spread is about one in six, the odds of MSU and UofM having such as bad/good weekend is no better than one in 36 or 2.8%, which is identical to the odds of rolling snake eyes with two dice in the game of craps. 

(Based on the actual numbers from the Normal Distribution, the odds of actually 2.5%, but who's counting.)

Even worse, the actual margins of victory were larger than just one standard deviation, and if I plug those numbers in the right formulas, the odds of such a miserable weekend for Spartan fans is actually much, much lower. It works out to be 5.5% x 7.7% = 0.39% or 1-in-250 or so. 

That is roughly equal to an upset where the spread is 37.5. The second biggest upset in recent history was Syracuse's 2007 upset of Louisville (-37). Based on some math that I did, an upset of this magnitude should only happen about once every 50 years.

The put things in further perspective, by some estimates, the "trouble with the snap" ending to the 2015 Michigan-Michigan State games only had about a 0.2% chance of happening. So, an outcome of the magnitude witnessed by Spartan fans or Wolverine fans who are into schadenfreude this weekend is only twice as likely as MSU's last second win in Ann Arbor in 2015.

So, if MSU fans think that the weekend was particularly unpleasant (or to any Michigan fans who this that this is all just normal), it is not likely to be repeated any time soon.

As a final bizarre tidbit, if we consider the higher odds of rolling snake eyes, that is roughly equivalent to the odds of an upset in a college football game where the spread is 27 points. The current spread of this weekend's MSU-UofM game is now right around 25 points. Let's just hope that the Spartan's luck will turn around soon.

Comments

Post a Comment

Popular posts from this blog

Dr. Green and White Helps You Fill Out Your Bracket (2024 Edition)

For as long as I can remember, I have loved the NCAA Basketball Tournament. I love the bracket. I love the underdogs. I love One Shining Moment. I even love the CBS theme music. As a kid I filled out hand-drawn brackets and scoured the morning newspaper for results of late night games. As I got older, I started tracking scores using a increasing complex set of spreadsheets. Over time, as my analysis became more sophisticated, I began to notice certain patterns to the Madness I have found that I can use modern analytics and computational tools to gain a better understanding of the tournament itself and perhaps even extract some hints as to how the tournament might play out. Last year, I used this analysis to correctly predict that No. 4 seed UConn win the National Title in addition to other notable upsets. There is no foolproof way to dominate your office pool, but it is possible to spot upsets that are more likely than others and teams that are likely to go on a run or flame out early....
Post a Comment
Read more

2024 Week Eight Preview: OK Computer

Playing the first game after a bye week is like waking up from a nap. It is a little tough to predict how the body will respond. If a nap comes at just the right time and lasts for just the right length of time, it can be very refreshing and rejuvenating. But sometimes waking up for a nap can be rough. It can cause a disorienting, groggy feeling like suddenly two plus two equals five and that down is the new up. Based on the way the three weeks prior to the bye week went, last week's break at the midpoint of the season came at exactly the right time for the Spartans. Facing one top five team is challenging enough. Facing two top five teams on consecutive weekends including almost 5,000 miles of travel is something else entirely. But how will the rested Spartans look on the field come Saturday night? It is hard to predict what we are going to get. It is the classic "rest versus rust," million dollar question.  I prefer to be optimistic and to believe that the Spartans will...
Post a Comment
Read more

2024 Week Seven Preview: Intermission

It is hard to believe that we are already halfway through the Michigan State Spartans' 2024 season. The Green and White currently sit at 3-3, having just lost two games straight to teams both ranked in the top three nationally.  Despite the current losing streak, Michigan State is actually slightly ahead of schedule. While the Spartans' schedule currently grades out to be harder than expected when I conducted the analysis this summer (by 0.7 games), Michigan State's current odds to go to a bowl game (46%) are 10 percentage points higher than what I projected.  In Week Seven, Michigan State has drawn a much needed bye. Think about it as an intermission of sorts. The Spartans' mission this weekend is to rest, heal, reflect on the first half of the season, and prepare for back half of the schedule with the goal of qualifying for the bowl game. Michigan State's team and staff may be taking it easy, but data and Vegas never sleep. Today's piece will focus more on the...
Post a Comment
Read more