Writers of Pro Football Prospectus 2008

Most Recent FO Features

KhanSha1.jpg

» Futures: My Expansion Franchise

You've just been awarded an NFL expansion team and must build your personnel department. How would you do it? Matt Waldman takes on the exercise.

20 Nov 2013

FEI Week 12: Halftime Adjustments

by Brian Fremeau

The Utah Utes took the ball on the first possession of the second half against Oregon on Saturday and drove 86 yards in eight plays for a touchdown. There were just over 10 minutes remaining in the third quarter and the Ducks were only leading 17-14. This moment prompted me to tweet that I couldn’t tell yet whether Utah was the bane of FEI’s existence or the greatest thing to happen to FEI.

The Utes appeared to be on their way to yet another close game against another top opponent, and at that point, I was thinking about how I was going to have to explain why a six-loss team was still in the top 10 of this week’s FEI ratings. De’Anthony Thomas and the Ducks had other plans.

DAT took the ensuing kickoff 86 yards for an Oregon touchdown to swing the lead back to nine points, and the Ducks dominated the second half from that point on. In a span of 13 non-garbage time minutes in the third and fourth quarters, Oregon outscored Utah 27-0, averaging 11.3 yards per play and allowing only 1.6 yards per play. The ultimately dominant victory bumped Oregon up two spots to No. 4 overall in this week’s ratings and knocked Utah down ten spots to No. 22.

This wasn’t the first time Oregon was involved in a relatively tight game in the first half before turning on the afterburners. Oregon led Washington State by only 10 points at the half back on October 19th and then scored 28 straight points to take a 62-24 lead with 13 minutes left in the fourth quarter. A week later, Oregon and UCLA were knotted at 14 points each midway through the third quarter before Oregon scored 28 straight to walk away with a 42-14 victory. Even their loss to Stanford on November 7 featured a furious rally in the fourth quarter for the Ducks to turn a 23-0 deficit into a 26-20 final score.

I was asked by a follower over the weekend whether there was a way to calculate first-half and second-half versions of FEI in order to measure the variability in performance for teams like the Ducks over the course of the game. I took on that challenge this week.

First-half FEI is relatively easy to calculate since all possessions except end-of-half clock kills are considered non-garbage time by my methodology. Oregon led Utah 17-7 through 13 non-garbage possessions of the first half, for a half-game efficiency of .220. Their game efficiency through all non-garbage possessions was 0.373. As a comparison, Florida State raced out to a 38-0 lead through 13 non-garbage first half possessions (0.835 half-game efficiency) and closed out non-garbage time early in the second half with a full game efficiency of 0.857.

It is important to note that calculating FEI ratings for all teams based on first half performance means that opponent-adjustments are based only the first half performances of those opponents. The top-10 in first-half FEI are listed below.

First Half FEI Top 10
1H
Rk
Team 1HFEI FEI
Rk
Rec FEI
1 Florida State .306 3 9-0 .305
2 Alabama .299 1 10-0 .315
3 Stanford .295 2 8-2 .308
4 Iowa .276 39 5-4 .085
5 Missouri .253 7 8-1 .248
6 USC .251 10 8-3 .226
7 Ohio State .250 9 9-0 .230
8 Wisconsin .247 8 7-2 .241
9 Baylor .242 6 8-0 .262
10 Arizona State .235 5 7-2 .272

Nine of the top-10 teams in overall FEI ratings also rank among the top-10 in first-half FEI, though their order shifts a bit. Florida State at No. 1 is not a surprise since the Seminoles have destroyed many of their opponents right from the opening kickoff and have pulled starters at or soon after halftime in several blowouts.

The big surprise is Iowa. A team ranked 39th overall with a 5-4 FBS record is the fourth-best first-half team? Indeed they are. Iowa has had a halftime lead in eight of their nine games this season, including first half "wins" over Northern Illinois, Michigan State, and Ohio State. Their only halftime deficit this season came against Wisconsin –- the Hawkeyes trailed 7-6 at the break before ultimately losing by a score of 28-9.

Can we calculate second half FEI the same way? No, unfortunately. Since garbage time kicks in very early in the second half in many blowout wins, the raw game efficiency measures are too variable for the FEI formula to make sense of them. However, we can calculate second-half FEI as a function of both full-game FEI and first-half FEI. Simply, second-half (including overtime) FEI and first-half FEI average out to full-game FEI.

Second Half FEI Top 10
2H
Rk
Team 1HFEI FEI
Rk
Rec FEI
1 Oregon .407 4 8-1 .288
2 Alabama .332 1 10-0 .315
3 Stanford .320 2 8-2 .308
4 Arizona State .310 5 7-2 .272
5 Florida State .304 3 9-0 .305
6 South Carolina .285 11 8-2 .222
7 Baylor .282 6 8-0 .262
8 Auburn .261 12 9-1 .213
9 Duke .259 26 7-2 .155
10 Mississippi .257 28 6-3 .144

And there’s Oregon, with an almost out-of-this world second-half FEI rating. The difference between the second-half FEI ratings of Oregon and No. 2 Alabama is the same as the difference between No. 2 Alabama and No. 10 Mississippi. Oregon is the only team that has outscored all of its opponents in second-half non-garbage possessions.

The first-half and second-half FEI ratings for all 125 FBS teams are posted here, ranked in order of overall FEI rating. The "record" of each team by half is calculated based on the results of non-garbage possessions in each half.

First Half FEI and Second Half FEI Ratings for Overall FEI Top 25
Rk Team Record FEI Rk 1H Rec 1HFEI Rk 2H Rec 2HFEI
1 Alabama 10-0 .315 2 10-0-0 .299 2 8-2-0 .332
2 Stanford 8-2 .308 3 8-2-0 .295 3 7-3-0 .320
3 Florida State 9-0 .305 1 9-0-0 .306 5 8-1-0 .304
4 Oregon 8-1 .288 17 7-1-1 .170 1 9-0-0 .407
5 Arizona State 7-2 .272 10 5-4-0 .235 4 6-1-2 .310
6 Baylor 8-0 .262 9 8-0-0 .242 7 6-2-0 .282
7 Missouri 8-1 .248 5 9-0-0 .253 14 6-2-1 .244
8 Wisconsin 7-2 .241 8 8-1-0 .247 15 7-1-1 .236
9 Ohio State 9-0 .230 7 7-2-0 .250 21 5-2-2 .211
10 USC 8-3 .226 6 8-2-1 .251 23 5-5-1 .201
11 South Carolina 8-2 .222 21 5-4-1 .159 6 7-3-0 .285
12 Auburn 9-1 .213 20 8-2-0 .164 8 8-2-0 .261
13 Oklahoma State 8-1 .211 19 8-1-0 .165 11 7-1-1 .256
14 BYU 6-3 .201 14 6-3-0 .184 18 6-3-0 .218
15 Texas A&M 7-2 .196 29 8-1-0 .137 12 7-2-0 .255
16 Georgia 5-4 .195 23 5-2-2 .154 16 4-5-0 .236
17 Michigan State 8-1 .192 15 7-2-0 .181 22 8-1-0 .202
18 Central Florida 8-1 .183 12 7-2-0 .204 28 6-3-0 .162
19 LSU 6-3 .180 26 6-3-0 .146 19 6-2-1 .214
20 UCLA 8-2 .175 13 7-2-1 .198 29 6-3-1 .152
21 Virginia Tech 6-4 .174 16 5-4-1 .172 25 7-3-0 .176
22 Utah 3-6 .165 31 3-6-0 .119 20 3-6-0 .212
23 Louisville 8-1 .163 11 8-1-0 .213 41 8-1-0 .114
24 Notre Dame 7-3 .159 27 6-4-0 .146 26 7-1-2 .173
25 Clemson 8-1 .158 18 6-2-1 .167 31 7-1-1 .148

The chart below represents the distribution of first half and second half team performances to date. The difference between first half and second half FEI for 67 teams is less than one half of one standard deviation. Oregon is one of 11 teams that have performed in the second half by more than one standard deviation better than they did in the first half, a list that also includes Mississippi, Washington, TCU, Duke, and Indiana. Ten teams were more than one standard deviation worse in the second half, a list that includes Iowa, Northwestern, and Nebraska.

FEI Week 12 Top 25

The Fremeau Efficiency Index (FEI) rewards playing well against good teams, win or lose, and punishes losing to poor teams more harshly than it rewards defeating poor teams. FEI is drive-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. FEI represents a team's efficiency value over average.

Other definitions:

  • SOS Pvs: Strength of schedule based on the likelihood of an elite team going undefeated against the given team's schedule to date.
  • SOS Fut: Strength of schedule based on the likelihood of an elite team going undefeated against the given team's remaining schedule.
  • FBS MW: Mean Wins, the average number of games a team with the given FEI rating would be expected to win against its entire schedule.
  • FBS RMW: Remaining Mean Wins, the average number of games a team with the given FEI rating would be expected to win against its remaining schedule.
  • OFEI: Offensive FEI, the opponent-adjusted efficiency of the given team's offense.
  • DFEI: Defensive FEI, the opponent-adjusted efficiency of the given team's defense.
  • STE: Special Teams Efficiency, the composite efficiency of the given team's special teams units - field goals, punt returns, kickoff returns, punts, and kickoffs.
  • FPA: Field Position Advantage, the share of the value of total starting field position earned by each team against its opponents.

These FEI ratings are a function of results of games played through November 16th. The ratings for all FBS teams can be found here. Program FEI (five-year weighted) ratings and other supplemental drive-based data can be found here.

Rk Team FBS
Rec
FEI LW GE GE
Rk
SOS
Pvs
Rk SOS
Fut
Rk FBS
MW
FBS
RMW
OFEI Rk DFEI Rk STE Rk FPA Rk
1 Alabama 10-0 .315 1 .370 3 .286 57 .606 19 9.8 .7 .433 14 -.705 4 5.942 1 .588 1
2 Stanford 8-2 .308 2 .160 19 .076 8 .836 51 10.1 1.9 .428 17 -.780 2 3.322 3 .566 6
3 Florida State 9-0 .305 3 .496 1 .501 94 .828 49 10.3 1.9 .544 10 -.632 7 -.370 80 .573 4
4 Oregon 8-1 .288 6 .369 4 .159 25 .738 36 9.4 1.7 .591 8 -.503 13 2.532 9 .569 5
5 Arizona State 7-2 .272 4 .136 26 .072 7 .623 24 8.3 1.6 .610 6 -.608 9 .413 56 .540 20
6 Baylor 8-0 .262 5 .419 2 .602 106 .529 14 9.8 2.4 .588 9 -.469 15 -.206 75 .541 18
7 Missouri 8-1 .248 7 .218 9 .334 66 .581 17 9.1 1.4 .278 31 -.558 10 -.502 87 .543 15
8 Wisconsin 7-2 .241 9 .230 8 .160 26 .896 66 8.9 1.8 .418 18 -.631 8 -.348 78 .514 48
9 Ohio State 9-0 .230 8 .306 6 .558 101 .787 43 9.8 1.7 .593 7 -.314 25 2.507 10 .557 9
10 USC 8-3 .226 13 .112 30 .090 12 .812 45 10.0 1.7 .340 21 -.734 3 1.008 36 .540 21
11 South Carolina 8-2 .222 10 .105 31 .178 28 .850 53 8.6 .7 .614 5 -.379 22 -2.752 119 .468 98
12 Auburn 9-1 .213 17 .136 25 .262 47 .488 11 8.5 .3 .375 20 -.480 14 2.994 6 .515 47
Rk Team FBS
Rec
FEI LW GE GE
Rk
SOS
Pvs
Rk SOS
Fut
Rk FBS
MW
FBS
RMW
OFEI Rk DFEI Rk STE Rk FPA Rk
13 Oklahoma State 8-1 .211 19 .186 15 .577 102 .617 22 9.1 1.3 .249 36 -.543 12 .703 46 .560 8
14 BYU 6-3 .201 11 .085 42 .232 40 .695 34 8.1 1.5 .111 52 -.639 6 -.131 72 .518 46
15 Texas A&M 7-2 .196 15 .184 16 .238 42 .354 6 7.7 .7 .765 1 .139 84 2.673 7 .566 7
16 Georgia 5-4 .195 16 .012 58 .136 18 .774 38 7.3 1.6 .686 2 -.016 63 .260 62 .463 103
17 Michigan State 8-1 .192 21 .193 13 .448 84 .894 65 9.2 1.7 .061 57 -.680 5 1.566 26 .588 2
18 Central Florida 8-1 .183 18 .212 10 .410 78 .956 88 10.1 2.8 .430 16 -.170 41 2.441 11 .542 16
19 LSU 6-3 .180 22 .128 28 .091 13 .780 39 7.4 1.5 .685 3 .082 75 2.181 15 .526 30
20 UCLA 8-2 .175 20 .138 24 .057 5 .367 7 7.3 .6 .269 32 -.469 16 2.105 16 .520 43
21 Virginia Tech 6-4 .174 14 .031 54 .139 19 .985 121 7.7 .9 -.019 65 -.871 1 -1.044 93 .493 71
22 Utah 3-6 .165 12 -.060 81 .027 2 .930 74 5.7 1.8 .317 26 -.309 28 .805 39 .475 94
23 Louisville 8-1 .163 27 .322 5 .659 111 .906 69 9.6 1.6 .389 19 -.332 23 1.580 25 .537 23
24 Notre Dame 7-3 .159 28 .050 49 .200 36 .268 2 7.5 .6 .434 13 -.259 32 .059 65 .492 72
25 Clemson 8-1 .158 35 .186 14 .340 67 .587 18 7.1 .3 .297 30 -.435 18 .045 66 .521 38

Posted by: Brian Fremeau on 20 Nov 2013

4 comments, Last at 22 Nov 2013, 5:21am by Brian Fremeau

Comments

1
by Kal :: Wed, 11/20/2013 - 1:37pm

This was absolutely awesome. I know it's about Oregon so I'm somewhat biased, but it's great to see this application of FEI to show how much a team is a first half or second half team.

The next step would be to see if there's any reasonable correlation between that and under or overperforming the model. My bet is that first half teams are 'better' than second half teams (and that 9 of the 10 top teams are that way kind of leans that way) but it'd be neat to see if there's anything that can be picked up.

2
by Aaron Brooks Go... :: Thu, 11/21/2013 - 11:06am

How many of Oregon's 20 points against Stanford came in "garbage time"? Because they didn't score at all until they were down 26 with 10 minutes left. Arguably only that last TD was non-garbage, which would mean Stanford outscored them 9-7 in the parts of the second half that mattered. Because Stanford certainly played the last 10 minutes like they were garbage time.

Also -- Stanford led 26-0 to before Oregon started their comeback. Which involved a fluke block kick -- you should talk to Aaron about that. Apparently you shouldn't consider events like that as having occurred -- they're non-predictive. =)

3
by Perfundle :: Thu, 11/21/2013 - 2:29pm

If the last TD was non-garbage, then by definition all previous TDs were also non-garbage. Are you going to argue that Michigan State scored garbage TDs during their 35-point comeback against Northwestern a few years back?

4
by Brian Fremeau :: Fri, 11/22/2013 - 5:21am

These two comments highlight a key difference in the way Bill and I calculate garbage time. I fall in the second camp here, garbage time includes every possession until the final outcome of the game has been determined. However fluky, Oregon played the final 10 minutes of the game and set itself up for an onside kick opportunity to potentially win the game in regulation. Until Stanford recovered that kick, the game was "non-garbage" by my definition. Bill falls in the first camp, that a large lead late in the fourth quarter has already entered garbage time, but that the game can then shift back to non-garbage time after garbage drives and scores have made it close again.