FEI Final Ratings
by Brian Fremeau
For the last decade, Alabama has held steady as one of the most consistently dominant programs in college football history. It isn't just that they claimed five national championships in that span, or that they played for the championship on two other occasions, or that they have finished the season ranked in the top five, if not top two, nearly every single year under Nick Saban. Their status as the top program in college football from 2009 to present has been supported by what they had never done as much as it has been supported by what they had done. They never suffered a dominant loss. Until Monday night.
Alabama lost by 28 points to Clemson in the College Football Playoff national championship game. They had previously never suffered a loss by more than 14 points under Nick Saban. From the start of the 2015 season through their semifinal victory over Oklahoma on December 29, a span of 58 games, they lost only three times by a combined total of only 21 points. Alabama could be beaten, but they couldn't be beaten down. Or so we thought.
The Clemson Tigers' 44-16 victory over Alabama to wrap up an undefeated championship season was extraordinary on many levels. They were physically dominant in the trenches, though it didn't show up in the box score, as both teams racked up similar stat lines on a total and per-play level. They didn't create more scoring opportunities than the Crimson Tide, they just capitalized on them far more frequently. They played their best when it mattered most, and looked spectacularly impressive doing it. Quarterback Trevor Lawrence made every difficult throw look easy and his receivers made every play that counted, including several one-handed grabs. Clemson's third-down conversion rate was otherwordly, considering their opponent had only allowed only a 31.9 percent third-down conversion rate coming into the game, and had allowed a conversion rate over 60 percent only twice previously in the last ten seasons -- against Johnny Manziel and Texas A&M in 2012 (61.1 percent) and in 2013 (62.5 percent). Clemson went 10-for-15 (66.7 percent) on third downs against the Tide, while facing an average distance to gain of 7.7 yards, and success on those plays turned what very well could have been a competitive down-to-the-wire classic into a blowout.
My numbers don't scrutinize performances at the play level, so a 62-yard completion on third-and-14 in the first quarter that led to Clemson's first offensive touchdown of the game isn't distinguished as an unlikely event in and of itself. Clemson scored a touchdown on a drive that started at its own 25-yard line, and FEI doesn't care whether they achieved that feat methodically, explosively, or otherwise. FEI does take note that Clemson's first touchdown on a 44-yard pick-six interception return, as well as its 46-yard interception return in the second quarter that set up a short field touchdown for the Tigers, are unique plays (specifically, the returns themselves) that don't necessarily represent sustainable possession efficiency. Call both plays opportunistic, and both were certainly great defensive stops against a previously near-flawless Alabama passing attack, but those two plays also inflated the final scoring margin a bit. My game splits calculated Clemson's combined offensive and defensive margin of victory to be 19.6 points -- better than any other performance against the Crimson Tide under Saban, but more along the lines of a three-score victory than a four-score one.
That distinction doesn't matter much, especially against what could and should still be considered an exceptionally formidable opponent. According to my single-game, opponent-adjusted GFEI ratings, Clemson's victory is clearly distinguished as the best of the season, and by a solid margin.
|Top 10 GFEI Single Game Performances in 2018|
|Team||Opponent||G Final||NG Final||GFEI|
|Clemson||Alabama||W 44-16||W 44-16||1.08|
|Alabama||LSU||W 29-0||W 22-0||0.92|
|Auburn||Purdue||W 63-14||W 56-7||0.88|
|Clemson||Notre Dame||W 30-3||W 30-3||0.84|
|Georgia||Georgia Tech||W 45-21||W 45-7||0.78|
|Missouri||Florida||W 38-17||W 38-17||0.75|
|Alabama||Oklahoma||W 45-34||W 45-27||0.71|
|Alabama||Georgia||W 35-28||W 35-28||0.69|
|LSU||Georgia||W 36-16||W 36-16||0.68|
|Florida||Michigan||W 41-15||W 41-15||0.68|
|G Final is final score including garbage time; NG Final is final score in non-garbage time|
Clemson also produced the fourth-best opponent-adjusted single game performance of the season nine days earlier in its semifinal victory over Notre Dame. That's what peaking when it matters most looks like, and it underscores how Clemson claimed the national championship in such impressive fashion. Still, there's something else that jumps off this list. Aside from Clemson, the best performances of the year were put forward by SEC teams, led first and foremost by Alabama. As far as FEI is concerned, the SEC stood out in its best moments, and as you might suspect, that means the SEC is looking awfully good in the final FEI ratings of the season.
For the third straight season, the national champion isn't ranked No. 1 in the final FEI ratings of the year, but rather No. 2. Alabama remains ahead of Clemson because they were so far ahead of the Tigers on the season to date; the 28-point loss head-to-head didn't fully overcome that difference. FEI doesn't adjust for recency, and Alabama's collective performances of the year, including a record of 7-1 against FEI top-20 teams, still compares favorably to Clemson's overall season (3-0 against top-20 opponents), even after the Crimson Tide laid an egg in the finale.
There are eight SEC teams ranked in the final FEI top 20, and three in the final FEI top 4. That, justifiably, will draw some perplexed reactions (including my own) to the merit of these ratings. Were both Georgia and LSU really as good as FEI suggests? How can five-loss Mississippi State, dominant on one side of the ball but not very special all around, really rank ahead of one-loss Notre Dame? Did the 2018 season "break" the FEI ratings? I'm not sure about any of these questions. The ratings are designed to measure something specific -- possession efficiency -- which usually parallels the eye test for most teams while still challenging our gut instincts about who is better than who. But this final set of ratings, more than any other I've produced previously, appears to have more opponent-adjustment peculiarities than usual. Perhaps that has something to do with this year's lack of connectivity. Perhaps I need to adjust or fix something in the formula that had been previously obscured. I'm going to have to take some time this offseason to examine these questions.
I was already planning on an offseason review of FEI in totality. Earlier this year I proposed a new format for the ratings output that is more tangible, and I think at a minimum I will make that change. I'm also scrutinizing FEI's predictive power. Projections this year were unremarkable, but I identified a few opportunities to isolate games in which FEI may have more predictive power than others. It will take a good amount of work, but I'm looking forward to a thorough review of FEI projections at both the game and season level so that I can be more transparent next year on what the system is and is not capable of in terms of predictive reliability.
I'm also interested in producing a companion set of ratings that better articulate achievement versus schedule rather than efficiency versus schedule. The most rabid debates in college football this year -- check that, every year -- revolve around competing perspectives on "best" versus "most-deserving," and I think there are better ways to frame those debates. Personally, I think that both perspectives are important. We don't crown the national champion based on its roster strength, but rather on what it has accomplished. Often, what it has accomplished meshes well with team strength. But sometimes, it doesn't, and the national champion earns the title by playing its best when it matters most rather than playing best more often over the course of the year.
I don't think it's taking anything away from Clemson to say that they were definitively the national champion in 2018, but they weren't definitively head and shoulders above Alabama, except on Monday night. And it's very healthy to remind ourselves that each game should be taken as a single outcome among many other results, and not necessarily the sole data point that distinguishes the two teams involved. Ohio State lost to Purdue by 29 points this year. Ohio State was not 29 points worse than Purdue this year. Both of those statements are true, and both are important.
In terms of merit, I introduced Elite Win Ratings this year as an output of achievement and not efficiency, and a better comparison with the College Football Playoff selection priorities. I adjusted the output somewhat to close out this year, now representing the adjusted wins (considering the strength of opponents faced) each team achieved. It is based on FEI, but it is a better representation of how accomplished each team was in 2018 rather than how efficient each team was in its games.
|Top 10 EWR Teams|
This output needs some offseason evaluation as well, both for its calculation and utility. But it feels more representative of what we prioritize most in our national champions, that they face elite challenges and win those that they face.
Both Clemson and Alabama distinguished themselves as the best teams this year, and every output I produce should reflect that. They also aren't going anywhere, and I fully expect both teams to be at or near the pinnacle of the sport next year and beyond. Clemson hasn't yet sustained a decade of dominance like Alabama, but they appear to have pulled even with, if not ahead of, the Crimson Tide in terms of current program power. It's not certain we'll get another playoff rematch next season, and I suppose some feeling of inevitability will again color our impressions of the season if they do dominate once again. But it's good to have two worthy adversaries rather than just one program head-and-shoulders above the rest. Cheers to Clemson, and cheers to college football rising to their challenge.
FEI Final 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 (SOS) represent the average number of losses an elite team (two standard deviations better than average) would have against the team's schedule. 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.