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

Popular posts from this blog

March Madness Analysis: Did the Selection Committee Get it Right in 2025?

I will be assembling my "usual" stats-based analysis of the bracket, complete with picks a little later this week (but before Thursday). For now, I had some thought on the bracket. In general, MSU's draw is about as good as fans could expect. I will go into more detail on that later. As for the job that the committee did... I am far from impressed. Once again, there are multiple errors in team selection, seeding, and bracketing as a whole. Let's look at each one in turn. Did the Committee get the right 68 teams? More or less. This is the area where I am the least concerned. As I mentioned yesterday, my metrics had UNC safely in the field and not even in the First Four, but I swapped them out for WVU at the last minute. UNC's single Q1 win gave me too much pause. I felt slightly vindicated when UNC made it.  My biggest beef is with Texas making it in at 19-15. That's just too many loses. Yes, they had 7 Q1 wins, but that also had 5 loses outside of Q1 and an ov...

Dr. Green and White Helps You Fill Out Your Bracket (2025 Edition)

For my money, we are all of the cusp of the best three weeks of the entire year. We just wrapped up two weeks of conference tournaments, but those were just an appetizer to the main course that is yet to come.  The powers that be gave us the menu on Sunday evening for the feast that is to come. Now it is time to enjoy a brief break and palette cleaner before we all make our selections. But what shall we choose? Which tasty little upset looks the best in the first round? Which teams are most likely to be sweet in the second weekend? Which quartet will comprise the final course? Over the years I have developed a set of analytics and computational tools to gain a better understanding of the mathematical underpinning of the NCAA Basketball Tournament. My methodology has a solid track record of correctly identifying upsets and sometimes doing more than that. In 2023, I used data to correctly predict that No. 4 seed UConn win the National Title. There is no foolproof way to dominate your...

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...