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

2025 College Football Analysis, Part Two: A Deep Dive into MSU's Schedule

In part one of this year's math-based preseason analysis of the college football season, we looked back at the 2024 season. Through that analysis, we learned about the historical accuracy of preseason polls (plus-or-minus 25 positions) and regular season win totals (plus-or-minus 2.5 wins). We also explored the impact of changes in ability, schedule, and luck. Now it is now time to shift focus to the 2025 season. Over the years I have developed and refined a way to simulate the entire college football season using schedule information and preseason rankings as the only inputs. I will soon go through the full details of what I learned from this exercise.  For today, I will focus exclusively on what it says about the Michigan State Spartans. We will take a close look at the Spartans' 2025 schedule from three different points of view. Opponent Overview The best place to start this analysis is with the simulation's inputs. Figure 1 below summarizes the preseason rankings (w...
Post a Comment
Read more

2025 College Football Analysis, Part Three: The Big Ten Race

So far in this year's math-driven college football preview, we have explored the historical accuracy of the preseason rankings, taken a look back at last year, and conducted a thorough analysis of the potential paths for the 2025 Michigan State Spartans' season. In today's installment, the focus shifts to the Big Ten conference race. Strengths of Schedule The first thing to cover today is relative strength of schedule. Figure 1 below summarizes my calculations for the 18 Big Ten teams' overall schedules. Figure 1:  Overall strengths of schedule for the 2025 Big Ten conference. The overall FBS rank is shown in each bar. There are several different ways to calculate strength of schedule. I use my preseason estimations of power rankings to generate estimated point spreads for all potential college football matchup. I then calculate the number of expected wins that a reference, borderline top 25 team would have if that reference team were to play the schedule in quest...
Post a Comment
Read more

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...
Post a Comment
Read more