Statistical Strength of Schedule

October 16, 2008

Something I cooked up last year that I think is worth doing again this year is my Statistical Strength of Schedule (SSOS) rankings. They are simpler to understand than some of the fancier ones out there, while also respecting the fact that seeing who won a game doesn’t tell the entire story. This contrasts with the NCAA’s schedule strength rankings, which only looks at opponents’ wins and losses.

It uses teams’ national rankings in total offense, scoring offense, total defense, and scoring defense. I get the average rank of a team’s opponents in those four categories, then average those four figures together. That is the SSOS score. The lower the score, the tougher the schedule. Here is an example of one team’s calculation, using Florida:

The Gators’ score is 64 points, good enough for the 47th-ranked schedule right now.

This formula downplays outliers by using the teams’ national ranks in the four categories. It adjusts for strange/unlikely game outcomes by using stat categories, since the better team doesn’t always win a game.

There is some noise, like when someone racks up huge numbers while blowing out cupcakes, but those tend to get evened out by the teams that don’t do much thanks to tough opponents. There will be some noise in any SOS rank as long as there’s not a balanced schedule across the board, which is to say there will always be noise.

The rank for any I-AA team in any category is 120. I am using the official NCAA stats, and they include games against I-AA teams. I do not have the time to go through everyone’s games to subtract out all I-AA games from the stats and recalculate the categories.

I also didn’t want to just lump all of Division I together like Jeff Sagarin does because I-AA teams play other I-AA teams almost exclusively, and the better I-AA teams would end up a lot higher than they should be. Instead, I just gave a blanket penalty to I-A teams for playing I-AA teams because they should know better. Western Kentucky counts as I-AA because the Hilltoppers are still reclassifying and not a full I-A member.

I held off until now to calculate the list so that teams can get a fair number of games under their belts. It’s a little weird right now because of the extra week in this season giving everyone an additional bye week. Most everyone has played six games, but there are a few overachievers who have reached seven already and a couple of slackers who have just played five.

Here is the opening top 25. Keep in mind that this can change wildly from week to week; last season, there would be a few teams that would move in excess of 30 spots in a single week. Keep in mind also that since a team’s opponents stats keep changing, more than just who you play in a week factors into movement; FAU once jumped 26 spots after a bye week last season.

  1. Washington, 34.75 points
  2. Wake Forest, 45.15
  3. Nebraska, 47.50
  4. New Mexico, 48.11
  5. Colorado, 51.67
  6. UCLA, 52.63
  7. Stanford, 52.71
  8. Utah State, 53.92
  9. Oregon State, 54.08
  10. Tennessee, 54.13
  11. USC, 54.85
  12. NC State 55.67
  13. FAU, 55.75
  14. Arkansas, 55.96
  15. Washington State, 56.50
  16. Michigan State, 56.61
  17. Arizona State, 57.04
  18. FIU, 57.33
  19. Temple, 57.46
  20. Toledo, 57.67
  21. Texas A&M, 57.83
  22. Ole Miss, 58.13
  23. Purdue, 58.38
  24. Syracuse, 59.17
  25. Michigan, 59.17

SSOS by Losses

When making charts, I group teams by losses rather than wins. People are generally more concerned about losses than wins when it comes to schedule strengthanyway, and it makes the imbalances in number of games played easier to deal with.

As you can see, the undefeated teams collectively have had the easiest schedules so far. The only unbeaten team with an SSOS in the top 40% is Alabama, with the 38th-ranked schedule and 62.42 points. Texas is the only other undefeated team even in the top 60%, with the 72nd-ranked schedule and 70.17 points. Penn State, if you’re curious, has the 89th-ranked schedule and 74.50 points.

This chart actually continues a trend I noticed last season. Among the teams that finished the regular season above .500, those with one or fewer losses unsurprisingly had the easiest collective schedules. However, after that it was the four-loss teams that had the next easiest combined schedules, followed by the five-loss teams.

If you project that everyone this season will repeat their first half performance or add an extra loss, that means that those teams with one or zero losses will have the easiest schedules. After that though, those projected to get four or five losses (who have two losses now) project to have the next easiest.

I don’t know why exactly teams with two losses (and last season four or five) buck the overall and expected trend. If anyone has any thoughts, feel free to leave them in the comments.

Quick Evaluations

This is normally where I would discuss the biggest gainers and fallers, but I can’t because it’s the first release. Instead, I am going to list some quick hits on a few teams in segments of the list.

Well Done: Michigan State. The Spartans are the only 6-1 team in the top quintile (20%) of the rankings. Also kudos to Wake Forest and USC for being the only other one-loss teams in the top quintile as both are 4-1.

Cheer Up: Washington. You may be winless, injury-ravaged, and perhaps soon to be without your head coach, but at least your futility has come against the toughest schedule by a significant margin.

For Shame: Clemson. Not only have the Tigers massively underachieved to the point that their coach has stepped down, they did it all against the 108th-ranked schedule so far.

Prove It: Oklahoma State, Penn State, Northwestern, UConn, Georgia Tech, Cal. These teams all have either zero losses or one loss and are currently in the fourth quintile (second from the bottom). They are doing well so far, but haven’t exactly faced the stiffest of competition on the whole yet.

Even after playing Missouri, Oklahoma State is solidly in this category with the 85th-ranked schedule.

Pretender Alert: BYU, Tulsa, Ball State, Texas Tech, Boise State, Utah. These teams are all undefeated, but they are also all in the bottom quintile. BYU is dead last at 100.42 points, followed by Tulsa at 92.79 points. Utah is right on the verge of being in the fourth quintile, a mere 0.37 points away from being there.

These teams may be victims of their own success to a degree, as big wins would depress the stats of their opponents, but that doesn’t tell the whole story. They all have simply played one of the 23 easiest schedules statistically.

Their brethren in the bottom quintile with one loss: FSU, Boston College, TCU, Kansas, USF, Western Michigan, Virginia Tech, and Cincinnati. Don’t get too excited on any of these guys quite yet either.

By Conference

Total Average SSOS for All 119 Teams: 67.92

Best Schedule: Washington, 1st overall, score of 34.75

Worst Schedule: Arizona, 115th, 91.25

Average SOS Rank: 36.90

Average SOS Score: 60.64

Best Schedule: Tennessee, 10th overall, score of 54.13

Worst Schedule: Kentucky, 76th, 71.83

Average SOS Rank: 48.00

Average SOS Score: 64.22

Best Schedule: Michigan State, 16th overall, score of 56.61

Worst Schedule: Penn State, 89th, 74.50

Average SOS Rank: 51.10

Average SOS Score: 65.22

Best Schedule: Nebraska, 3rd overall, score of 47.50

Worst Schedule: Texas Tech, 111th, 85.54

Average SOS Rank: 57.55

Average SOS Score: 66.77

Best Schedule: Syracuse, 24th overall, score of 59.17

Worst Schedule: USF, 106th, 79.17

Average SOS Rank: 63.00

Average SOS Score: 68.43

Best Schedule: Wake Forest, 2nd overall, score of 45.15

Worst Schedule: FSU, 113th, 85.90

Average SOS Rank: 69.58

Average SOS Score: 70.38

Closing Note

It’s still just half way through the season, so there’s no reason to get offended over your team’s schedule just yet. Those teams that played two I-AA teams (i.e. Texas Tech, FSU) have some work to do to get out of the basements of their conferences, but tougher teams lay ahead.