FEI Week 14 Ratings
In what may eventually be remembered as the "most 2020" game of the 2020 season, undefeated BYU traveled to undefeated Coastal Carolina to play on Saturday in a game that had not been on the books as of the writing of this column last Wednesday. The game did not disappoint, with the two teams trading both figurative and literal blows over 21 non-garbage possessions, concluding with a dramatic 81-yard potential game-winning drive by BYU that was stopped 1 yard shy of the end zone with a game-saving tackle by the Chanticleers. The game encapsulated everything we love about college football and then some, with unusually high-profile stakes attached to what would have been a very low-profile game on paper at the start of the year, doused in the absurd urgency of 54-hours-notice-game-of-the-year vibes.
The College Football Playoff committee, however, wasn't expected to give the game much more than a passing nod, and they didn't. Coastal Carolina and BYU simply switched positions in the CFP rankings this week -- BYU dropped from 13th to 18th, and Coastal jumped from 18th to 13th. I don't know if that is at all inconsistent with how the playoff committee has treated Power 5 teams in similar positions over the years, but there are plenty of indicators that suggest that both BYU and Coastal Carolina should already have been higher heading into the game, and that a close loss by either team should not have been an albatross.
Consider the Power 5 teams currently ranked in the CFP top 12 that have suffered only one loss to date this season. No. 3 Clemson had a 47-40 double-overtime loss to No. 2 Notre Dame on the road. No. 5 Texas A&M had a 52-24 loss to No. 1 Alabama on the road. No. 6 Florida had a 41-38 loss to No. 5 Texas A&M on the road. No. 10 Miami had a 42-17 loss on to No. 3 Clemson on the road. No. 12 Indiana had a 42-35 loss to No. 4 Ohio State on the road.
FEI has all of the same teams ranked this week among its top 17. But it also has BYU hanging in at No. 4 following its 22-17 loss to No. 10 Coastal Carolina on the road.
This isn't to suggest that FEI is a better playoff ranking system than the selection committee, and I've been very quick to admit that the FEI formula this year may struggle to discern the relative strengths of teams in particular due to the lack of interconnectivity between conferences. But I do want to underscore that the reason BYU and Coastal Carolina are both buoyed by the FEI system is similar to the same logic that buoys Clemson in relation to Notre Dame; Florida and Texas A&M in relation to Alabama; and Indiana in relation to Ohio State. When two elite, good, or average teams play one another, especially in a tightly contested game, logic suggests that they are still elite, good, or average teams on the other side of that outcome.
And in BYU's case, even after suffering its first loss of the season and scoring only 17 points, they still lead the nation in every raw net efficiency category I track. Is their schedule strength on par with the Power 5 one-loss teams getting love? No, but it isn't way worse. For example, an elite team (two standard deviations better than average) would be expected to lose 0.29 more games against Florida's schedule to date than against BYU's schedule to date. A good team (one standard deviation better than average) would be expected to lose 0.83 more games against Clemson's schedule to date than against BYU's schedule to date. And an average team would be expected to lose 0.62 more games against Indiana's schedule to date than against BYU's schedule to date. Those schedule-strength variations need to be balanced against raw efficiency, and it's a challenge to find the right balance. My biggest complaint with the committee is that they seem to treat the relative schedule strengths of Group of 5 teams as far worse than they actually are.
There's something else interesting that the big game results named thus far point to, and that's home-field advantage. Due to the coronavirus pandemic, there are reduced capacity crowds at every sporting event, and for several teams and conferences, no fans in attendance at all. This has led to speculation that home-field advantage may be at an all-time low, or potentially even a non-factor in game outcomes. It's too selective a sample to point to the road losses by BYU, Clemson, Florida, Texas A&M, Miami, and Indiana as indicators that home-field advantage is as strong as it has ever been, but it made me wonder.
A deeper study of home-field advantage could certainly be developed to explore this hypothesis, but I thought it would be interesting to simply calculate the average margin of victory of home teams in conference games from 2007 to present. Conference games aren't a completely neutral data set, strictly speaking, but we would expect to find more balance between opponents (as opposed to strong teams almost exclusively playing host to weak teams in non-conference games) in such a sample. If 2020 is an outlier due to severely diminished crowds, conference-game home-field advantage data should reveal that impact.
Home-field advantage in conference games in 2020 by this calculation is only +1.9 points per game, a full 0.9 points less than the +2.8 points per game average over the 14-year span. This could be the indicator of the impact of crowds on home-field advantage that we hypothesized, but there are other recent seasons with comparably small home-field advantages drawn from the data. In 2018, the conference game home-field advantage was only +2.0 points per game, and in 2014 the conference game home-field advantage was at an "all-time" (since 2007) low, at only +1.8 points per game. Neither of those two seasons, nor any of the other games in the span, had any obvious systemic factors such as COVID to suggest home-field advantage should be dramatically impacted. And the relatively steady betting line trend over the last seven seasons suggests that the wisdom of crowds has been picking up not on a precipitous change in home-field advantage, but on something more like a year-over-year trend.
This is just the start of a deeper dive I'd like to take on the subject in the offseason. For one thing, I may be using these overall trends to make subtle changes in the manner in which I apply home-field advantage to FEI ratings and FEI game projections. There are also sample-size variations to consider, but it would be well worth exploring the degree to which these changes are or are not consistent across individual conferences -- perhaps especially in the wake of conference realignment shake-ups that have happened over the span.
Are there any other hypotheses to consider? We've been conditioned to treat the packed and electric atmosphere of an 80,000-seat stadium as an intimidating environment that can be a difference-maker in a big game. But I've been skeptical over the years of how much the crowd itself really matters in comparison to the other factors in play related to home versus road scenarios -- the travel, disruptions to routines, familiarity with the facilities, weather, etc. BYU and Coastal Carolina played in front of only 5,000 fans. Would a full house of 20,000 or more have made a bigger difference, were the unique travel circumstances of this game a bigger factor, or was home field not actually much of a factor in Conway, South Carolina, at all?
The same questions apply to Clemson and Notre Dame on November 7, and Indiana and Ohio State on November 21, and in every game this season. The biggest games remaining will almost exclusively be hosted at neutral-site locations, in conference championship games, bowl games, and ultimately, playoff semifinals and finals. And it may be a long time, hopefully not too long, before we'll repopulate stadiums with full houses and gather more data to indicate whether this is an outlier or a trend.
2020 FEI Ratings (through Week 14)
FEI ratings (FEI) represent the per-possession scoring advantage a team would be expected to have on a neutral field against an average opponent. Offense ratings (OFEI) and defense ratings (DFEI) represent the per-possession scoring advantages for each team unit against an average opponent unit. FEI, OFEI, and DFEI ratings are based on a combination of opponent-adjusted results to date and preseason projections.
Net points per drive (NPD) is the difference between points scored per offensive drive and points allowed per opponent offensive drive. Net available yards percentage (NAY) is the difference between offensive available yards percentage and opponent offensive available yards percentage. Net yards per play (NPP) is the difference between drive yards per offensive play and drive yards allowed per opponent offensive play. Three different schedule strength ratings for games played to date are provided, based on current FEI ratings, representing the expected number of losses an elite team two standard deviations better than average would have against the given team's schedule (ELS), the expected number of losses a good team one standard deviation above average would have against the schedule (GLS), and the expected number of losses an average team would have against the schedule (ALS).
Ratings and supporting data are calculated from the results of non-garbage possessions in FBS vs. FBS games.