Introducing CTR: Cumulative Team Ratings for College Football Teams

 

(Article written by me, is from Week 14 of the 2018 College Football Season, as seen in Wake Forest University’s newspaper the Old Gold and Black)

About the Rankings:

The rating system is relatively simple, compared to other complex computer algorithms. It is imperfect, and with any rating system it is no doubt going to have some head scratchers.

However, the beauty of this system is that it ranks teams based on their cumulative performance throughout the season. It is meant to be a number that measures a team’s overall performance. It is based on three factors, Win Percentage, Strength of Schedule, and Schedule/Outlier Adjusted Margin of Victory.

 

Factor 1: W-L% (Wins/Games Played)

This one is the most simple of the three, as there are no adjustments made. It is simply a team’s wins divided by their total games played.

 

Factor 2: Strength of Schedule

((2/3 x Opp’s W-L%) + (Opponent’s Opponent’s W-L% x 1/3)) x 1.6

Strength of schedule metrics come in all shapes and sizes. Depending on which metric you use, a team like Oklahoma could have one of the 10 toughest schedules in the country or one that is ranked in the hundreds. Mine is simple; however I am planning on making adjustments to it in order to make it so a 7-5 Iowa State team is not worth the same in one’s SOS as a 7-5 Wyoming team.

There are adjustments that currently exist in my model to deal with this facet, however they do not seem to fully adjust for it.

The SOS Metric is determined by 2/3 x opponents W-L% + 1.3 of their opponent’s opponent’s W-L%. The number attained after this is weighted by a factor of 1.6 in order to give more emphasis on a team’s SOS. This is because SOS already lacks variance therefor a team ranked #1 in SOS is statisicaly not that much different than a team ranked #20 in SOS.

Factor 3: Schedule/Outlier Adjusted Margin of Victory:

Part 1: ((Team Pts-Opp Pts)/G) x .5) + (Median Margin of Victory x .5))

Part 2: ((Average Opponent’s Pts-Opponents Opponents Pts)/G) x .5) + *(Median (Average MOV of Opponents x .5)) x Coeff (Depends on the year usually ~1.6)

(Part 1 + Part 2) x CoEff (Depends on the year usually ~ .7)

*This can be confusing, but this means the Median of the Average MOVS of their opponents. For Example if a team played teams with Average MOVS of 6, 9, 10, this would be 9.

The Margin of Victory is no doubt the most controversial metic in terms of advanced college football computer ratings. Some metrics such as Colley do not factor it in at all and other models are entirely based on MOV such as SRS. My formula takes this fact into account by weighting it in order to not give it too much of an impact. The catalyst for this being that at the end of the day, football is about winning no matter the final score.

Despite that statement, if two teams beat a common opponent but one team blows them out of the water by 35, while the other one wins by 3, the blowout is a much better indicator of relative strength.

My model averages the mean scoring margin s. FBS Teams with the Median MOV in order to adjust for outlier performances. This is factored in with the average median and Mean MOV of their opponents to adjust for strength of opponents. However, the SOS aspect of the metric is weighted greater than the team’s own MOV.

*There also end of season adjustments that give the True National Champion bonus points

Here is an Example of the Metric given the Top 25 rankings pre conference Title Weekend this past season (Week 14):

1. Georgia Bulldogs 11-1 SEC Rating: 67.01
2. Wisconsin Badgers 12-0 Big 10 Rating: 66.39
3. Auburn Tigers 10-2 SEC Rating: 66.19
4. Alabama Crimson Tide 11-1 SEC Rating: 65.05
5. Ohio State Buckeyes 10-2 Big 10 Rating: 64.81
6. UCF Knights 11-0 AAC Rating: 64.64
7. Clemson Tigers 11-1 ACC Rating: 64.59
8. Notre Dame Fighting Irish 9-3 Ind: 63.96
9. Penn State Nittany Lions 10-2 Big 10 Rating: 62.12
10. Oklahoma Sooners 11-1 Big 12 Rating: 62.12
11. Washington Huskies 10-2 PAC 12 Rating: 60.24
12. Miami Hurricanes 10-1 ACC Rating: 60.00
13. USC Trojans 10-2 PAC 12 Rating: 59.86
14. TCU Horned Frogs 10-2 Big 12 Rating: 58.45
15. Memphis Tigers 10-1 AAC Rating: 58.36
16. Stanford Cardinal 9-3 PAC 12 Rating: 58.04
17. Michigan State Spartans 9-3 Big 10 Rating: 57.65
18. FAU Owls 9-3 C-USA Rating: 55.34
19. Iowa Hawkeyes 7-5 Big 10 Rating: 55.10
20. Boise State Broncos 9-3 MWC Rating: 55.03
21. Northwestern Wildcats 9-3 Big 10 Rating: 54.95
22. Washington State Cougars 9-3 PAC 12 Rating: 54.82
23. Michigan Wolverines 8-4 Big 10 Rating: 54.19
24. Toledo Rockets 10-2 MAC Rating: 54.64
25. Miss State Bulldogs 8-4 SEC Rating: 54.19