by Brian Fremeau
FEI ratings are back this week after some work-life balance items got in the way last week. And we're not just returning to our regularly scheduled programming, we have much more data to dig into this week. Now that we have eight weeks of college football data to parse, I've eliminated preseason projected data from the FEI formula; introduced a new adjusted possession efficiency output; published offensive, defensive, and special teams ratings pages; and rolled out my opponent-adjusted single game performance ratings, GFEI.
We'll start with the new column in a prominent position on the FEI overall ratings page, Adjusted Possession Advantage (APA). Though I have made subtle changes to the FEI formula over the years, I've consistently kept its output in the same format, despite that format not having a clear translation to its meaning. An elite team may have an end-of-year FEI rating of 0.300, and average team would have a rating of 0.000, but what did those terms mean? I haven't changed this formatting (yet), in part because I haven't settled on an alternative. APA may be that alternative, but I'm going to run it alongside FEI this year before making an official decision on it.
APA represents the per-possession opponent-adjusted scoring advantage a team would have over an average opponent. An elite team with a .300 FEI rating might not be easily translated, but an elite team with a 2.97 APA rating (as Alabama has this week), can be more easily translated. On every possession exchange against an average opponent, Alabama would be expected to score nearly three more points than its opponent. That translational change alone has me strongly considering formatting FEI in this manner going forward. But APA isn't simply a conversion of FEI to a scoring-over-average value. It also represents a fundamental change in the way opponent-adjustments are made in my formula. In the simplest terms I can describe, FEI leans more heavily on single-game performances against top teams, and APA leans more heavily on season-long efficiency data rather than single game data.
Clemson ranks No. 1 overall in FEI this week, and No. 2 in APA. Alabama ranks No. 1 in APA and No. 2 in FEI. The reason for this flip is Clemson's most recent victory over previously undefeated North Carolina State, a 41-7 thrashing of the FEI No. 17 team in the nation. That game performance (.983 percentile) accounts for 23.4 percent of Clemson's FEI rating. Alabama hasn't had the opportunity to play a team of North Carolina State's caliber yet to date -- their 39-10 victory over FEI No. 23 Missouri is the toughest test they've faced -- and that victory only represents 17.0 percent of their overall FEI rating. FEI essentially gives Clemson extra credit for their dominance over the Wolfpack.
But APA doesn't view that game as significantly as does FEI. Alabama has been more consistently dominant than any other team this year, and APA finds that to be more impressive than a single dominant performance like Clemson's over North Carolina State. The Crimson Tide have single-game opponent-adjusted percentile performances through eight games as follows:
- .597 vs FEI No. 119 Louisville
- .794 vs FEI No. 105 Arkansas State
- .990 vs FEI No. 61 Ole Miss
- .966 vs FEI No. 31 Texas A&M
- .903 vs FEI No. 129 Louisiana Lafayette
- .975 vs FEI No. 73 Arkansas
- .992 vs FEI No. 23 Missouri
- .978 vs FEI No. 82 Tennessee
(Click here for GFEI single game performance data for every team.)
Alabama has had six single performances in the 90th percentile, whereas Clemson has had only three. APA considers Alabama's consistency in elite performances to be a better indicator of future success than Clemson's weighted single-game performance against a better team than Alabama has faced to date. I have a hunch that this change may be preferred by season's end as a better approach, but I'll likely need to produce and examine APA's retrodictive and predictive performances versus FEI in the off-season before committing to this change long-term. Again, for the remainder of this year, I'll run both columns each week.
As for my offensive, defensive, and special teams ratings pages, you'll notice a few more columns sprinkled into these as well. On the special teams page, I've dropped the starting field position columns that used to accompany these ratings since I now have that data split out now in a new format on my site. I've added in opponent field goal efficiency and team and opponent extra point efficiency in order to comprehensively represent each of the non-offensive and non-defensive values generated over the course of each game. I've also made SFEI an opponent-adjusted version of special teams efficiency, as I previously had not found a suitable way to represent those opponent adjustments.
The offensive and defensive pages will look more familiar, but I added a new column to each representing "Ball Control Rate." This was inspired by long-time reader and Oklahoma State fan David Hudson, who asked me recently to look into an issue he perceived to be plaguing his Cowboys. He suggested that their seemingly unusual propensity to be a boom-or-bust offense that, whether successful (explosive plays) or not (three-and-outs), put its defense in position to return to the field too quickly. I dug into a boom-or-bust offenses a while back, but I decided to flip the idea into the offenses that control possession, not in terms of time elapsed on the clock but rather in terms of the number of plays run before giving the ball back to its opponents. An elite offense like Alabama's, scoring touchdowns on 63.2 percent of non-garbage drives so far this year, is scoring very quickly. The Crimson Tide have the nation's best touchdown rate and the nation's best rate at avoiding three-and-outs, but they only rank 45th in ball control rate. North Carolina State and Army, both ranked among the top 10 in opponent-adjusted offense, rank No. 1 and No. 2 respectively in ball control rate.
Oklahoma State, meanwhile, has had more ball control success this year than Dave had suspected. The Cowboys rank 20th in ball control rate through Week 8, higher than they do in touchdown rate (26th) or its first down rate (29th). Perhaps a different measure of ball control would result in a different output, and perhaps I'll need to explore historic data in this category before drawing deeper conclusions. I'm open, as always, to feedback.
FEI Week 8 Ratings
The Fremeau Efficiency Index (FEI) is a college football rating system based on opponent-adjusted possession efficiency. Adjusted Possession Advantage (APA) ratings represent the per-possession scoring advantage a team would be expected to have on a neutral field against an average opponent, calculated as a function of current FEI overall, offense, defense, and special teams ratings.
Strength of Schedule ratings (PSOS) represent the average number of losses an elite team (two standard deviations better than average) would have against the team's regular season schedule to date. Offensive FEI (OFEI) is scoring value generated per drive adjusted for starting field position and opponent defenses faced. Defensive FEI (DFEI) is scoring value generated per opponent drive adjusted for starting field position and opponent offenses faced. Special Teams FEI (SFEI) is scoring value generated per possession by a team's non-offensive and non-defensive units adjusted for opponent special teams units faced. The team's record to date against opponents ranked in the FEI top 10 (v10), top 20 (v20), top 30 (v30), top 40 (v40), and top 50 (v50) are also provided.
Ratings and supporting data are calculated from the results of non-garbage possessions in FBS vs. FBS games.