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21 Oct 2009

Week 7 FEI Ratings

by Brian Fremeau

At last, we have arrived at the middle of October. We have finally shed all preseason projection data and can examine the 2009 college football season through a clean lens. 342 FBS vs. FBS games have been played to date. From this point forward, only those games are considered. How well have teams played?

There are two key components to that question. The first is answered by Game Efficiency, the raw assessment of a team's scoring efficiency over the non-garbage possessions of a game. The second requires context: How efficient was each team relative to the strength of its opponents? Now that the noise of preseason projected data has been filtered away, we can examine the FEI methodology as it relates to that question for offenses, defenses, and entire teams.

There may be no better week to introduce this year's adjusted Offensive FEI and Defensive FEI metrics for the first time. According to the latest FEI ratings, a top-5 offense played a top-5 defense twice in Week 7, the first such occasions of the 2009 football season. On Thursday night, Cincinnati's No. 3 offense defeated South Florida's No. 5 defense. On Saturday, USC's No. 2 defense stopped Notre Dame's No. 1 offense in a dramatic finish. Obviously, the game outcomes were influenced by many factors, plays, and drives, but can we isolate these particular unit performances?

Cincinnati possessed the ball 14 times in non-garbage play, scoring four touchdowns (on drives of 3, 84, 74, and 70 yards) and kicking two field goals. The Bearcats attempted a third field goal from the 23-yard line, punted six times and threw one interception. With Cincinnati's starting field position, an average offense against an average defense would expect to score 27.9 points. Cincinnati's offense earned 34.6 points of drive-ending value (four touchdowns and three field goal opportunities). The Bearcats' raw Offensive Efficiency (OE) for the game was .239, or 24 percent greater than average.

Notre Dame possessed the ball 11 times in non-garbage play, scoring four touchdowns (on drives of 56, 78, 68, and 13 yards) and attempting no field goals. With their starting field position, an average offense would expect to score 22.0 points. Notre Dame earned 27.8 points of drive-ending value, producing an OE of .276.

The USC and South Florida defenses have held teams well below average scoring expectations this year, and we run the raw OE numbers through several adjustment iterations to determine a recalibrated Offensive FEI (OFEI) rating for the game. Notre Dame's OFEI against USC was 1.570 (roughly 160 percent stronger than average); Cincinnati produced an OFEI of 1.372. Reciprocally, the performances of the USC and South Florida defenses should be measured against the prolific scoring expectations of the high-powered Notre Dame and Cincinnati offenses. USC produced a Defensive FEI (DFEI) rating of -1.263 (roughly 130 percent stronger than average); South Florida produced a DFEI rating of -.972.

Note that strong offensive efficiency produces a rating above zero and strong defensive efficiency produces a rating below zero. Also note that offensive and defensive efficiency are calibrated in each adjustment iteration for the purposes of equivalency. Since the best offenses can be much more prolific than the best defenses in terms of raw efficiency, standard deviations are used to balance the scales of offensive and defensive data. Thus, it may be accurate to describe Notre Dame's offense as having played roughly 160 percent stronger than average against USC, and USC's defense as having played roughly 125 percent stronger than average against ND -- but the two terms are not directly comparable.

Notre Dame's offensive performance was the sixth-best of the season in college football; Cincinnati's ranked 19th. USC's defensive performance was eighth-best of the season in college football; South Florida's ranked 34th. Table 1 lists the top 5 in each category over the first 342 games of 2009.

Top-5 Offensive Performances of 2009 to Date
Off FEI Offense Defense Game Outcome Field
Position
Value
Drive
Ending
Value
Opp.
DFEI
Rank
1.881 Texas Tech Kansas State W (66-14 in 26 poss.) 15.5 51.5 87
1.854 Notre Dame Nevada W (35-0 in 20 poss.) 7.6 34.8 119
1.831 Navy Ohio State L (27-31 in 22 poss.) 15.6 27.8 8
1.635 Georgia Tech Virginia Tech W (28-23 in 22 poss.) 16.2 27.8 16
1.595 Iowa State Kansas L (36-41 in 24 poss.) 18.2 37.1 31
Top-5 Defensive Performances of 2009 to Date
Def FEI Defense Offense Game Outcome Field
Position
Value
Drive
Ending
Value
Opp.
OFEI
Rank
-1.706 South Florida Florida State W (17-7 in 30 poss.) 28.2 9.2 8
-1.552 Clemson Georgia Tech L (27-30 in 31 poss.) 22.4 21.3 2
-1.460 Iowa Iowa State W (35-3 in 25 poss.) 14.0 1.6 24
-1.450 Miami Georgia Tech W (33-17 in 19 poss.) 15.5 16.4 2
-1.391 Iowa Arizona W (27-17 in 25 poss.) 14.0 2.8 21

Remember that the actual FEI ratings for all teams include an additional "relevance of data" factor and are not a simple average of each team's cumulative OFEI and DFEI data. Performances against stronger competition, win or lose, is rewarded, but dominant performances against weak competition receives less relevance weight in the formula.

Top-5 Team Performances of 2009 to Date
FEI Team Opponent Game Outcome Off
FEI
Def
FEI
Opp.
FEI
Rank
0.770 Virginia Tech Miami W (31-7 in 27 poss.) 1.424 -1.263 5
0.714 Miami Georgia Tech W (33-17 in 19 poss.) 1.151 -1.450 8
0.649 Alabama Virginia Tech W (34-24 in 32 poss.) 0.936 -1.196 3
0.644 Michigan Iowa L (28-30 in 31 poss.) 1.423 -0.896 2
0.626 Nebraska Virginia Tech L (15-16 in 26 poss.) 0.460 -1.103 3

Week 7 FEI Top 25

The principles of the Fremeau Efficiency Index (FEI) can be found here. Like DVOA, FEI rewards playing well against good teams, win or lose, and punishes losing to poor teams more harshly than it rewards defeating poor teams. Unlike DVOA, it is drive-based, not play-by-play based, and it is specifically engineered to measure the college game.

FEI is the opponent-adjusted value of Game Efficiency (GE), a measurement of the success rate of a team scoring and preventing opponent scoring throughout the non-garbage-time possessions of a game. Like DVOA, it represents a team's efficiency value over average. Strength of Schedule (SOS) is calculated as the likelihood that an elite team would win every game on the given team's schedule. New This Week: SOS is calculated only from games already played, and does not include future games scheduled.

Only games between FBS teams are considered in the FEI calculations. Preseason projections are no longer included in the calculations. FEI ratings are a function of results of games played through October 17th.

FEI ratings for all 120 FBS teams are now listed in the stats page section of FootballOutsiders.com. Click here for current ratings, or here for 2008 ratings.

Rank Team FBS
W-L
FEI Last
Wk
GE GE
Rk
SOS SOS
Rk
OE OE
Rk
Off
FEI
OFEI
Rk
DE DE
Rk
Def
FEI
DFEI
Rk
FPA FPA
Rank
1 Alabama 7-0 0.300 2 0.335 2 0.313 20 0.282 23 0.395 15 -0.760 1 -0.628 3 0.553 12
2 Iowa 6-0 0.29 5 0.183 16 0.347 27 -0.065 67 0.356 16 -0.555 10 -0.702 1 0.538 25
3 Virginia Tech 5-2 0.281 3 0.174 17 0.088 1 0.307 18 0.462 9 -0.306 29 -0.456 16 0.547 18
4 Cincinnati 5-0 0.279 11 0.314 3 0.472 48 1.073 1 0.605 3 -0.310 28 -0.269 32 0.494 69
5 Miami 4-1 0.276 4 0.066 42 0.184 5 0.183 32 0.292 22 -0.037 52 -0.524 9 0.508 50
6 Florida 5-0 0.265 1 0.298 5 0.587 77 0.217 28 0.415 12 -0.638 4 -0.543 6 0.542 21
7 TCU 5-0 0.264 7 0.251 8 0.526 61 0.037 53 0.426 11 -0.599 8 -0.352 22 0.559 8
8 Georgia Tech 5-1 0.263 12 0.056 46 0.161 3 0.482 12 0.751 2 0.327 102 0.005 60 0.506 53
9 USC 5-1 0.249 8 0.22 10 0.313 21 0.241 27 0.291 23 -0.607 6 -0.647 2 0.504 57
10 Boise State 5-0 0.235 10 0.344 1 0.654 91 0.419 13 0.217 28 -0.533 13 -0.447 17 0.552 14
11 Arizona 3-2 0.211 20 0.009 54 0.176 4 0.175 33 0.294 21 0.195 84 -0.223 34 0.512 41
12 Texas 6-0 0.203 6 0.306 4 0.539 67 0.042 52 0.200 33 -0.657 3 -0.397 20 0.576 3
Rank Team FBS
W-L
FEI Last
Wk
GE GE
Rk
SOS SOS
Rk
OE OE
Rk
Off
FEI
OFEI
Rk
DE DE
Rk
Def
FEI
DFEI
Rk
FPA FPA
Rank
13 Oregon 5-1 0.187 19 0.216 11 0.454 47 0.076 46 0.153 39 -0.628 5 -0.476 13 0.522 32
14 Texas Tech 4-2 0.184 35 0.268 6 0.382 34 0.683 5 0.404 14 -0.512 14 -0.290 30 0.497 66
15 Notre Dame 4-2 0.183 21 0.134 25 0.359 28 0.901 2 0.770 1 0.152 79 -0.091 49 0.473 93
16 Ohio State 5-2 0.162 9 0.184 15 0.478 50 -0.012 60 0.064 51 -0.509 15 -0.526 8 0.549 17
17 Oregon State 3-2 0.158 33 0.056 45 0.369 31 0.297 20 0.182 37 0.277 96 -0.060 51 0.535 27
18 Oklahoma 2-3 0.156 13 0.166 20 0.237 9 0.070 50 0.076 50 -0.553 11 -0.517 11 0.495 68
19 LSU 5-1 0.155 24 0.125 26 0.403 37 -0.093 74 0.023 58 -0.392 22 -0.313 26 0.529 29
20 South Florida 3-1 0.149 14 0.104 33 0.451 45 0.131 37 -0.251 94 -0.397 21 -0.567 5 0.492 71
21 Clemson 3-3 0.145 30 0.122 27 0.295 16 -0.294 97 -0.012 63 -0.535 12 -0.532 7 0.550 16
22 Wisconsin 4-2 0.138 22 -0.010 58 0.285 13 0.072 49 0.102 46 -0.044 49 -0.516 12 0.488 80
23 Michigan 4-2 0.136 29 0.138 22 0.243 10 0.260 25 0.183 36 -0.218 34 -0.471 14 0.503 60
24 Kansas 4-1 0.136 16 0.202 13 0.910 119 0.545 10 0.242 26 -0.124 39 -0.279 31 0.546 19
25 Pittsburgh 5-1 0.135 18 0.135 23 0.800 111 0.301 19 0.144 40 0.124 76 -0.011 56 0.541 22

Posted by: Brian Fremeau on 21 Oct 2009

6 comments, Last at 23 Oct 2009, 9:49am by Brian Fremeau

Comments

1
by Paulo Sanchotene, RS, Brazil (not verified) :: Wed, 10/21/2009 - 2:36pm

It seems that Weiss must do two things:

a) kill the clock whenever and in all ways possible; and
b) call Romeo Crennel -is he still unemployed?- urgently to work that defense...

2
by zlionsfan :: Wed, 10/21/2009 - 2:59pm

Go Boilers! Best 2-5 FBS record in the country. (It was better when Purdue was 1-5 last week ... Washington State was the only other 1-5 team. There are several other 2-5 teams this week, but they all played an FCS team.)

3
by ChiTown11111 (not verified) :: Thu, 10/22/2009 - 12:31am

It seems like Iowa is defiantly getting hosed by the voters in the BCS, they are 3rd in the computers right now and 3rd in FEI while the Coaches and Press are afraid to put them in the top 5.

4
by Muldrake (not verified) :: Thu, 10/22/2009 - 1:17pm

These numbers look a lot better since taking out the projections and seem closer to what we're actually seeing on the field. I especially like the fact that strength of schedule takes into account only games actually played now as well. It will be interesting to see how this affects the accuracy of the weekly picks, which haven't been horrible but haven't been doing as well as the SP+

5
by MJRuffalo (not verified) :: Thu, 10/22/2009 - 6:38pm

From the looks of your SOS ratings I see one glaring flaw. It does not seem that you are taking home or road games into account. Please correct me if I am misreading this.

6
by Brian Fremeau :: Fri, 10/23/2009 - 9:49am

The SOS calculation data includes where the game was played. Home field advantage is a component.