Big ups to 18S regular Scarponi for helping us out with the arduous task of working the chart into a much more user-friendly format that shows win probability rather than loss probability. His 18S Award-Winner Free Subscription For Life is now secure!

As we noted last week, we’re filling in for the Reddit dude last year who created a Python script to do these charts for every FBS team. Well, sort of filling in; we’re just doing Notre Dame, because we’re very self-centered people. He got too much harassment from stupid fans about why he was so mean to their team in his preseason charts this year, so he stopped. Nice job there by the math-deficient in the college football fan base…

Recapping the methodology again: These aren’t actual SP+ win probabilities, as SP+ creator Bill Connelly doesn’t publish those regularly after his preseason previews. We used a slightly tweaked version of the formula that the Reddit guy reverse-engineered to get close to published probabilities. That formula does some probability magic on the differential in SP+ rating for the two teams (with a bump for home field). I applied this formula to the preseason ratings and nudged it a bit until most of the probabilities were within 1-2 percentage points of Connelly’s published numbers, and will rely on that formula for the rest of the season. So it won’t exactly match the official win probability for each game but it’ll be close enough for our purposes.

Post-Week 3 Update

Notre Dame's 2019 Week 3 SP+ Win Probability Matric

As to how to read this chart:

As you move down each column, you find the probability of Notre Dame owning that many wins at that point of the schedule. In the first row, you can see that the probability of owning 0 wins through week 1 is 0% and one win is 100%, since we already won. Same for the New Mexico row. The matrix shows that the most likely outcome after our third game is two wins, after fourth game is three wins, and so on. The 4.1% figure in the Stanford line translates to our chances to be 12-0 at this point. The color coding ranges from green for the most probable outcome to red for the least probable. From this chart, you can see that SP+ predicts 10-2 as our most likely season record at 34.8%.

In the last row, we’re tracking how much the probability of each win total has changed from the previous week. This is largely a function of our own outcomes, the quality of play that led to those outcomes, and SP+’s changing perceptions of our opponents. The demolition of New Mexico combined with poor showings by a number of opponents sent win probabilities (mostly) skyrocketing this week; note that the probabilities of 10-2, 11-1, and 12-0 all jumped substantially while those for everything 9-3 or worse fell. In fact, 10-2 or better is at the moment comfortably the most likely season outcome, with a 60.6% probability; that’s up from 43.1% last week.

Other Nuggets

  • Tackling the “Big Three”: We mentioned last week that USC might vault Stanford into this group that also includes Georgia and Michigan. After each russet-mantle-clad opponent yakked on the road, I think they can stay right where they are. Also last week, I said this: “I have a sneaking suspicion that Michigan’s impending visit to Wisconsin will shift” wins over Michigan and Stanford and a loss to Georgia to the most likely Big Three scenario. Turns out we didn’t have to wait – that is the most likely outcome now at 33.4%, with losses to Georgia and Michigan and a win over Stanford next at 29.1%. The probability of sweeping the Big Three sits at 10.7%.
  • Taking care of business: Notre Dame’s expected win total jumped about half a game this weekend, to 9.74 wins. If the Irish handle their business in all the games they “should” win – defined for these purposes as having a SP+ win probability of 70% or higher – that expectation jumps to 10.78 wins. That’s also half a game higher than last week.
  • Price check on Charmin, please: Before the season, Notre Dame’s schedule looked to be extremely top-heavy with some maybe-decent middle teams and a pretty light bottom. After three weeks, that top-heavy portion looks really close to being one team, which is you-know-who. The win probability for Michigan started at 39% preseason and has moved to 53%, with plenty of reason to believe it could be higher by the time the game comes around. The next-lowest win probability is 79% against Virginia. Meaning as bad as you feel about facing Georgia this week, SP+ at this point says that USC, Stanford, Virginia, et al. should feel worse about facing Notre Dame.
  • Carole King would be proud: Movement galore as many Irish opponents had a rough week; literally every single individual game win probability increased. To wit:
    • USC moved 12.7 points to 79.9% after falling in overtime at BYU.
    • Boston College moved 9.7 points to 92.4% after getting humiliated at home by Kansas. BY KANSAS. AT HOME.
    • Virginia moved 6.9 points to 78.6% after struggling against a weak Florida State team (so much fun to write that).
    • Michigan moved 4.7 points to 53.4% after sitting idle; Middle Tennessee State lost at home to Duke worse than they lost to the Skunkbears in Ann Arbor.
    • Stanford moved 4.5 points to 82.6% thanks to a not-as-close-as-the-score-indicates 45-27 loss to UCF.
    • Virginia Tech moved 4.3 points to 84.0% thanks to a true dogfight with FCS Furman, secured only when they covered an onside kick with 1:49 remaining.
    • Georgia moved 2.9 points to 24.3%, probably due to a combo of Notre Dame looking good against New Mexico and Louisville looking better than Vandy so far.
    • Duke moved 2.5 points to 82.0%; not really sure why, given that they played well against MTSU as noted, but I’ll take it.
    • Navy moved 0.6 points to 96.6% after an idle week.
    • Hapless Bowling Green, not wanting to be left out, moved up 0.3 points to 99.8%. They’re going to have to ration themselves if they want to keep playing this game.

Lead photo attribution:, Paul Sancya, AP