October 16, 2021

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The Education Specialists

FBS Mathematical Preview: College Football Playoff and New Year’s Six

So far this summer, I have performed an in-depth, data-driven analysis of Michigan State’s football schedule, the Big Ten race, the rest of the Power Five and the FBS independents and Group of Five. Today, it is time to put all of those pieces together and to make some predictions as to what teams will make the College Football Playoff as well as the other four New Year’s Six bowl games.

In the previous parts of this series, I have presented data tables for every conference that included College Football Playoff odds for all 130 FBS teams. Table 1 below shows the 25 teams with the best odds to make the playoffs along with each team’s preseason ranking, strength of schedule (with the national ranking in parenthesis) and the odds for those teams make the final game and to win the national championship.

Note that my strength of schedule calculation is based on the number of expected wins for an average Power Five with that schedule and therefore a lower number means a harder schedule.

Table 1: Top 25 playoff, final game, and national title odds based on the results of a 100,000-cycle Monte Carlo simulation

In general, the playoff odds mirror the preseason rankings fairly closely with a few notable exceptions. The top-five teams appear in order, with the exception of Alabama. The defending champions are the consensus No. 1 team in the preseason, but the Crimson Tide grade out with only the fourth best odds to make the playoffs (24 percent) behind Ohio State (27 percent), Oklahoma (30 percent) and Clemson (39 percent).

The reason for this is essentially the difference in the strengths of schedule, where Alabama has one of the top-10 most difficult schedules, while the remaining challengers have schedules outside of top 30. Clemson in particular has one of the easiest schedules in the entire Power Five (ranked No. 67 overall) which helps to explain the large difference in playoff odds between the Tigers and the rest of the field.

That said, the national title odds for the top-four teams all range from between nine and 12 percent per team, and Alabama’s odds leapfrog Ohio State’s odds. In other words, if Alabama can survive the SEC gauntlet, the Crimson Tide’s odds go up since, on paper, they are the best team in the country.

For the rest of the top-25, deviations between the preseason rank and the College Footbal Playoff odds rankings are usually due to differences in of strength of schedule. The main exception to this rule is Notre Dame.

The Fighting Irish have one of top-25 most difficult schedules, but their playoff odds ranking (No. 6) is noticeably higher than their preseason ranking (No. 11). This seems to be purely due to the fact that as an independent, Notre Dame does not have to play in a conference championship game.

As we learned during Big Ten basketball season, the best way to ensure that a team does not lose is simply to not play. This “strategy” appears to boost Notre Dame’s playoff odds.

Just looking at Table 1 suggests that Clemson, Oklahoma, Ohio State and Alabama are most likely quartet of teams to make the College Football Playoff this year. Based on the raw odds, that is essentially true. However, when I crunch the numbers on different combinations of those top-four in the playoffs, I get the result shown in Figure 1.

Figure 1: Distribution of the different combinations of the preseason top four teams in the College Football Playoff based on the Monte Carlo simulation. (Note that Clemson is labeled simply as “C”)

According to this figure, if my calculated odds are correct, it is likely that only one or two teams from the group including Clemson, Oklahoma, Ohio State and Alabama will make the CFP. This data also suggest that none of the those four teams making the playoffs is a more likely scenario than three or all four members of the group making it.

On one hand, this is not surprising. My results say that Clemson makes the playoffs in almost 40 percent of the simulations. However, this also implies that in 60 percent of the simulations the Tigers do not make the playoffs. So Figure 1 does seem to follow from the numbers in Table 1.

In addition, this distribution reminds me a bit of distribution of No. 1 seeds that make the Final Four in the NCAA Tournament in basketball. Both simulation and history tells us that only one or two top seeds usually advance to the final weekend.

But, football these days is a different animal. First of all, the odds that I give for the top teams to make the playoffs are low compared to the odds that can be derived from the current Las Vegas money line (which give the top-four teams between a 60 and an 80 percent chance to reach the CFP).

Furthermore, a retrospective analysis of the past seven years suggests that between two and three of the teams that start the season in the top-four usually end the season in the playoffs. I would expect (and in fact project) that trend to continue in 2021.

What this highlights is a potential weakness in my simulation methodology: I treat all teams equally. I assume that all teams are equally likely to be both better than expected and worse than expected. In reality, however, teams like Clemson and Alabama, at least over the past few years, rarely underachieve. They consistently “beat the odds” which is why they are so dominant. That seems likely to continue this year. That said, these trends are often only trends until they aren’t.

As a final piece of data related to the big picture aspects of the College Football Playoff, Figure 2 give the odds that at least one team from each conference will make the playoffs (on the left) and the odds that more than one team from each league will be invited (on the right).

Figure 2: Distribution of the numbers of teams from each conference in the Playoffs, based on the results of the 100,000-cycle Monte Carlo simulation.

In a nutshell, the SEC is most likely to get at least one team, and also most likely to get multiple teams, into the College Football Playoff, which is not a surprise. After that, the ACC and the Big Ten have the best odds. Interestingly, the Big 12 has better odds than the Pac-12 to get one team into the playoffs, while the Pac-12 has better odds to get multiple teams.

I suspect that this is due to the fact that the Pac-12 has divisions and the Big 12 does not. A team like Oregon could be edged out of the division race by Washington and still make the College Football Playoff. In the Big 12, however, the team that loses in the conference championship game is most likely out of the CFP, and the third-place team’s odds are likely longer than the odds of division runner-up from another conference.

Disruptive Playoff Prediction

With the data shown above, I could simply make my College Football Playoff predictions by taking teams with the best four odds and then slotting the next eight or so teams in the New Year’s Six bowls. Based on the average outcome of my 100,000 simulations, this is perhaps what is most likely.

However, the reality of the situation is that eventual CFP and NY6 participants are not selected based on averages. Teams are selected based on the outcome of one very specific scenario: the actual results of a full season of football. In order to make a more interesting projection of the 2021 postseason, I instead turn to my “disruptive” simulation.

As I summarized in the previous installments of this series, my disruptive simulation tweaks the parameters in order to create a historically reasonable number of total upsets. In my preview of each conference, I summarized the expected records for all teams assuming that the favored teams all win and if I “disrupt” the simulation.

Table 2 gives a summary of the division and conference races in both scenarios.

Table 2: Summary of the division and conference races base on the raw odds and if the simulation is disrupted with the insertion of upsets.

This table is divided into two parts. The left side shows the odds-based favorite in each division, which is the equivalent to the favorite if the preseason rankings are correct and if there are no upsets. Basically, the highest ranked team in the preseason always wins. The odds for each team to win the division are shown and the team favored to win the conference championship game is shaded in green.

The right-hand side gives the results of each conference race in the disruptive simulation. I have also included the projected record for each team following conference championship games in this scenario, as well as key wins and losses. The divisions where there is a change in the winner between the two simulations are highlighted in yellow.

In addition to the teams that the disruptive simulation projects to play for a conference championship, Table 3 summarizes the notable remaining Power Five teams with two or fewer losses overall.

Table 3: Projected records and notable wins and losses for other CFP and NY6 contenders based on the disruptive simulation.

For the purpose of my “official” College Football Playoff projections, I will use the more interesting results from disruptive simulation.

If the season were to play in this manner, Clemson would emerge as the lone undefeated team and would obviously be given the No. 1 seed in the CFP. Ohio State, at 12-1 with several quality wins would be the obvious option as the No. 2 seed, but the other two slots are less straightforward.

In this scenario, Texas A&M is a two-loss SEC champion with some high quality wins. I think that the Aggies would earn the No. 3 seed. Then, it would most likely come down to Big 12 Champion Oklahoma, at 12-1 or Notre Dame at 11-1. I think that the CFP committee would have to give the nod to Oklahoma in this case as the No. 4 seed with the message that winning a conference title trumps Notre Dame’s accomplishments (Sorry, Irish, but if you don’t like it, go join a conference).

So based on the current bowl rotation, the College Football Playoff would set up as follows in this scenario (with the projected point spreads shown):

  • Orange Bowl: No. 1 Clemson (-1) versus No. 4 Oklahoma
  • Cotton Bowl: No. 2 Ohio State (-2) versus No. 3 Texas A&M

In this scenario, Clemson would be expected to face Ohio State (+1.5) in the national title game, where the Tigers would be a narrow favorite.

As for the other New Year’s Six bowls, based on the projected standings and season results summarized above, I would expect the following matchups (with the projected spreads shown):

I could also see Alabama and Florida trading spots, but my pairing produces a likely more competitive set of games (based on the preseason rankings) and also avoids an Alabama/Notre Dame rematch from last year’s semifinal.

As for the Fiesta Bowl, Utah makes a surprise appearance as the last remaining one-loss team. I pair the Utes with the best Group of Five team in Cincinnati, as the Bearcats would edge out the Boise State and UL Lafayette with a slightly better resume.

Note that there are a few teams that I do not project to secure a New Years’ Six slot but who would project to be a tough out in a bowl game, including Georgia, Oregon and North Carolina. That trio consists of all consensus top-10 teams in the preseason, but they all have tricky schedules.

So, that is what the math says about the 2021 college football season. While this is all well and good, it would be nice to know if all of this math that I have done might actually be useful in the betting market. After all, my simulation projects odds that can be directly compared to many of the same odds for various season outcomes as set by our friends in Las Vegas.

In the final installment of my preseason college football analysis, I will dig into these number in more detail to provide a preseason dose of Bad Betting Advice. Stay tuned and Go Green.