Writers of Pro Football Prospectus 2008

23 Sep 2015

FEI Week 3: Early Returns

by Brian Fremeau

The college football season is only three weeks young and the playoff selections are still months down the road, but several big game results are already in the books. This past weekend featured upset home losses from both the Alabama Crimson Tide (No. 2 in the Associated Press and Coaches polls last week) and the USC Trojans (No. 6 and No. 7 in the polls), which may loom large as the rest of the season plays out, both inside the respective conferences and in the national playoff chase.

The FEI ratings weren't shaken up as dramatically, but that's because the FEI ratings are still significantly influenced by preseason projections. Each week through the first half of the season I reduce the weight of preseason projected data. This week, the preseason data receives 57 percent of the weight and game results to date receive only 43 percent. Starting with the ratings released following Week 7, the FEI ratings will be purely a function of current year data.

Since preseason data is still a big influence, Alabama retains the top spot in the FEI ratings this week and USC dropped only three spots from No. 16 to No. 19. The Oregon Ducks lost to Michigan State in Week 2 and have clung to their No. 3 ranking in FEI due to the same preseason projection influence.

The early season FEI ratings don't overreact to individual game results, something I consider to be a feature of the ratings rather than a fault. I expect that the success and accuracy of FEI game projections will be relatively consistent through the first half of the season, as they have been so far. And even though some individual ratings may appear to be locked into preseason expectations, individual team win likelihoods have been impacted.

Alabama, Oregon, and USC may still be ranked at or near their preseason projected rankings, but each have received a blow to their projected win totals. The Crimson Tide now have a projected total of 9.7 mean wins (down from 10.2 in the preseason), while Oregon sits at 9.6 mean wins (down from 10.5) and USC sits at 7.5 mean wins (down from 8.4). Those drops are all in the bottom third of changes in mean wins projections from preseason to today, but they aren't the most dramatic downshifts in expected wins.

South Carolina (5.8 total mean wins, down from 7.9) and Arkansas (4.7 total mean wins, down from 6.7) have had the worst starts of the year in comparison to preseason FEI projections. Auburn hasn't looked good either, of course, but the Tigers have only dropped from 7.3 to 6.7 total mean wins so far. All three SEC teams have had early trouble defensively, and all three have a top-15 strength of schedule, which will provide little relief in the weeks ahead.

The Northwestern Wildcats are on the high end in terms of making an immediate positive impact on their mean wins projection. Northwestern was ranked No. 54 in the preseason FEI projections with a total mean wins projection of 5.9 wins (4.9 FBS wins plus one FCS win). With wins over Stanford, Duke, and FCS Eastern Illinois under their belt, and an upcoming schedule of opponents that have not boosted their own ratings, they've bumped their projection to 8.7 total mean wins and are currently ranked 35th in FEI.

The tables below identify the ten teams that have boosted their mean wins projections and the bottom ten teams that have had their mean wins projections nosedive since the start of the year.

Top 10 Mean Wins Boost Since Preseason Bottom 10 Mean Wins Drop Since Preseason
Team Then Now Delta Team Then Now Delta
Northwestern 5.9 8.7 +2.8 Colorado State 8.2 7.1 -1.1
Ohio 5.5 7.4 +1.9 Western Michigan 6.6 5.4 -1.2
BYU 7.6 9.4 +1.8 Utah State 8.2 6.9 -1.3
Texas A&M 7.0 8.8 +1.8 New Mexico State 3.8 2.5 -1.3
Clemson 8.7 10.2 +1.5 Kent State 6.8 5.4 -1.4
Buffalo 4.9 6.3 +1.4 Central Florida 7.7 6.2 -1.5
Toledo 8.5 9.9 +1.4 Louisville 8.2 6.6 -1.6
Houston 7.4 8.7 +1.3 San Diego State 7.7 5.7 -2.0
Temple 8.2 9.5 +1.3 Arkansas 6.7 4.7 -2.0
Mississippi 9.0 10.3 +1.3 South Carolina 7.9 5.8 -2.1

FEI Week 3 Ratings

The Fremeau Efficiency Index (FEI) is a college football rating system based on opponent-adjusted drive efficiency. Approximately 20,000 possessions are contested annually in FBS-vs.-FBS games. First-half clock-kills and end-of-game garbage drives and scores are filtered out. Unadjusted game efficiency (GE) is a measure of net success on non-garbage possessions, and opponent adjustments are calculated with special emphasis placed on quality performances against good teams, win or lose. Other definitions:

  • SOS: Strength of Schedule, measured as the likelihood of an elite team going undefeated against the given team's regular season schedule. Schedule strength data based on FEI ratings and calculated across other dimensions can be explored in this interactive visualization.
  • FBS MW: Mean Wins, the average number of games a team with the given FEI rating would be expected to win against its regular season schedule of FBS opponents.
  • FBS RMW: Remaining Mean Wins, the average number of games a team with the given FEI rating would be expected to win against the remainder of its regular season schedule of FBS opponents.

Preseason projections are a function of program strength and trajectory as well as transition factors including returning starters and recruiting success. The weight given to preseason projections is reduced in the FEI formula over the first half of the season until it is eliminated entirely following the results of Week 7. Preseason projection data receives 57 percent of the weight in this week's ratings. Ratings for all FBS teams can be found here.

Rank Team FBS
W-L
FEI LW GE GE
Rk
SOS SOS
Rk
FBS
MW
FBS
RMW
1 Alabama 2-1 .285 1 .202 18 .095 7 9.4 6.7
2 Ohio State 3-0 .255 2 .225 12 .434 73 11.1 8.4
3 Oregon 1-1 .228 3 .126 31 .182 27 9.1 7.6
4 Baylor 1-0 .226 4 .400 1 .260 45 9.4 8.5
5 Mississippi 2-0 .213 14 .224 13 .115 10 8.5 7.3
6 Georgia 3-0 .211 5 .295 9 .183 28 8.8 6.0
7 UCLA 3-0 .207 7 .247 11 .204 34 9.8 7.1
8 Michigan State 3-0 .206 6 .160 29 .202 33 10.0 7.6
9 TCU 2-0 .200 8 .097 41 .235 41 8.8 7.0
10 LSU 2-0 .199 9 .219 14 .080 3 8.1 6.6
11 Clemson 2-0 .196 13 .209 15 .316 59 9.0 7.2
12 Notre Dame 3-0 .193 11 .176 25 .206 35 9.4 6.9
13 Stanford 2-1 .188 19 .114 33 .232 38 9.3 7.1
14 Georgia Tech 1-1 .184 10 .188 22 .143 17 7.8 6.5
15 Texas A&M 3-0 .177 17 .301 8 .072 2 7.2 4.8
Rank Team FBS
W-L
FEI LW GE GE
Rk
SOS SOS
Rk
FBS
MW
FBS
RMW
16 Florida State 3-0 .175 12 .281 10 .322 61 8.9 6.1
17 Arizona State 1-1 .168 15 .015 59 .168 26 7.8 6.4
18 Oklahoma 3-0 .161 18 .193 21 .198 32 8.9 6.3
19 USC 2-1 .156 16 .329 6 .108 8 7.9 5.5
20 Kansas State 2-0 .145 23 .149 30 .328 62 8.1 6.2
21 Boise State 1-1 .142 20 -.041 74 .606 106 9.5 8.2
22 Missouri 2-0 .131 21 .054 53 .288 54 7.6 5.8
23 BYU 2-1 .130 29 .052 54 .267 47 7.6 6.4
24 Virginia Tech 1-1 .129 24 .011 61 .279 52 7.7 6.6
25 Wisconsin 2-1 .124 25 .179 24 .272 49 9.4 7.3
26 Mississippi State 1-1 .120 27 .090 46 .094 6 6.1 4.8
27 Nebraska 1-2 .108 31 .113 36 .394 71 8.6 6.5
28 Auburn 1-1 .108 22 -.176 98 .084 4 5.5 4.7
29 Utah 3-0 .106 30 .204 17 .167 25 7.3 5.0
30 Oklahoma State 2-0 .105 32 .316 7 .315 58 7.1 5.3

Posted by: Brian Fremeau on 23 Sep 2015

3 comments, Last at 24 Sep 2015, 2:07pm by rgrunder

Comments

1
by rgrunder :: Wed, 09/23/2015 - 4:59pm

Looks like an error in Clemson's MMW boost above. I'm assuming they were at 7.2 in the preseason and are now at 8.7? Thanks.

2
by Brian Fremeau :: Thu, 09/24/2015 - 5:26am

Thanks, I fixed the table. Clemson's mean wins went up from 8.7 to 10.2 since the preseason.

3
by rgrunder :: Thu, 09/24/2015 - 2:07pm

As a Clemson fan, no--thank YOU!