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25 Sep 2013

FEI Week 4: Yards per Stop

by Brian Fremeau

College football can be unpredictable at times, but this past weekend was not one of those times. Week 4 featured a handful of exciting games, but ultimately very few surprises. Favorites won 42 of the 44 FBS vs. FBS games this past weekend. (The fewest number of upsets in any weekend that featured at least 40 games last season was seven.)

FEI projections correctly picked only 37 winners; that was better than expected as well. I include a Projected Win Expectation (PWE) for each game, and that data provides a baseline expectation of success rate for FEI game projections. Based on PWE, FEI expected to pick 34 out of 44 games correctly in Week 4. On the season, FEI has been expected to pick 138 out of 173 (.797) FBS vs. FBS games correctly. FEI has actually picked 137 right (.792).

A weekend like this one might have suggested that the FEI ratings would remain relatively stable, but that wasn’t the case. Michigan, Notre Dame, Michigan State, and Oregon State all slipped out of the FEI top 25 even though three of those four won over the weekend. Georgia Tech, UCLA, Baylor, and Texas Tech all moved up into the FEI top 25. Seven teams moved up at least 20 ranking positions, and Missouri vaulted unexpectedly into the FEI top 10.

The reason for most of these changes had more to do with the continued reduction in weight of preseason data in the FEI formula than with the results of the weekend. And since some teams have only played two FBS opponents, the weight shift for preseason data can have a big impact. At this point in the season, preseason data accounts for around 25 percent of each team’s rating. In three weeks, we will have eliminated preseason data from the formula altogether.

There were a handful of ridiculously uncompetitive blowouts as well. Ohio State and Miami outscored FCS opponents Florida A&M and Savannah State by a combined score of 153-7. Louisville beat Florida International 72-0. Mississippi State beat Troy 62-7. Baylor dominated Louisiana Monroe 70-7 ... through three quarters. The Bears didn’t score over the final 22:51 of the game and still won by 63 points.

Baylor has only played two weak FBS opponents so far (ULM and Buffalo), but the Bears have been spectacularly efficient in those games on offense. On non-garbage possessions, Baylor has earned at least one first down on 100 percent of its drives. They have earned 84.2 percent of available yards. They have averaged at least 10 yards per play on 52.6 percent of possessions. They have averaged 5.5 points per drive. They have had 16 non-garbage possessions start on their own side of midfield; 13 of those crossed into opponent territory, and 12 of them reached the end zone.

I synthesize offensive efficiency as a measure of actual drive success versus expected drive success based on field position. The full data sets for offensive and defensive efficiency will be published in three weeks, but it should come as no surprise that Baylor is the early front-runner in this overall offensive efficiency metric. The challenge in publishing offensive efficiency (and many of our stats) is that the output (percentage better or worse than average) is not as tangible for fans as standard stats.

I received an e-mail inquiry last week from reader Chris Healey, who asked if I could look into a new approach for offensive and defensive success rates. Chris specifically wanted to know how successful each team is in moving the ball without its opponent forcing a stop.

For instance, a team that strings together consecutive 70-yard touchdown drives and then throws an interception on the first play of its third possession will have earned 140 yards before being stopped. If its opponent goes three-and-out on its first three possessions of the same game, it will have earned fewer than 10 yards per stop to that point.

Chris wanted to know what this would look like over the course of an entire season. He suggested that this "Yards per Stop" stat captures offensive efficiency in an effective way because it combines scoring success with field position and tempo adjustments, but delivers it in terms of football’s basic unit of measure: yards. I like this concept because it reminds me of the origins of FEI. When I first started working with the drive data sets that would eventually produce FEI, I was interested in measuring each team’s ability to string together consecutive successful possessions. Yards per Stop has similar potential.

I started with 2012 data since we have sample size issues for 2013 this early in the season. I eliminated garbage time possessions and scores just as I do with FEI data. The tables below identify the top-10 offenses and defenses in terms of Yards per Stop; each team’s rankings in the FEI data I usually supply is also provided for reference.

2012 Yards Per Stop - Top Offenses
Rank Team Yds/Stop OE OE
Rank
FD FD
Rank
AY AY
Rank
Va Va
Rank
PPD PPD
Rank
1 Louisiana Tech 87.6 0.774 2 0.797 5 0.656 2 0.632 1 3.68 1
2 Texas A&M 85.0 0.987 1 0.824 2 0.657 1 0.609 2 3.33 4
3 Baylor 79.5 0.735 3 0.825 1 0.641 3 0.608 3 3.31 5
4 Oregon 76.8 0.615 4 0.748 20 0.589 5 0.544 4 3.53 2
5 Northern Illinois 69.6 0.579 5 0.771 10 0.588 7 0.539 6 3.21 6
6 Nevada 69.3 0.576 6 0.801 3 0.589 6 0.540 5 3.01 10
7 Alabama 68.2 0.496 9 0.780 8 0.590 4 0.515 8 3.36 3
8 Georgia 65.0 0.465 12 0.707 44 0.557 14 0.504 16 3.03 9
9 Marshall 64.1 0.492 10 0.759 17 0.559 13 0.500 17 2.88 14
10 Oklahoma 64.0 0.534 7 0.794 6 0.574 8 0.508 12 2.84 17

2012 Yards Per Stop - Top Defenses
Rank Team Yds/Stop DE DE
Rank
FD FD
Rank
AY AY
Rank
Va Va
Rank
PPD PPD
Rank
1 Alabama 25.2 -0.725 1 0.537 4 0.301 1 0.230 3 0.88 1
2 Florida State 25.6 -0.566 5 0.532 2 0.309 3 0.224 1 1.25 9
3 Michigan State 26.0 -0.591 4 0.535 3 0.328 5 0.227 2 1.19 7
4 BYU 26.1 -0.647 2 0.523 1 0.309 2 0.267 10 1.01 2
5 Florida 28.0 -0.601 3 0.562 7 0.341 8 0.275 13 1.19 8
6 Connecticut 28.1 -0.416 17 0.564 8 0.335 7 0.252 5 1.50 21
7 Fresno State 28.4 -0.445 13 0.553 5 0.327 4 0.259 8 1.39 13
8 Wisconsin 29.2 -0.394 20 0.553 6 0.330 6 0.255 7 1.41 15
9 South Carolina 29.3 -0.496 11 0.621 28 0.362 16 0.292 18 1.45 18
10 Bowling Green 29.3 -0.438 15 0.580 12 0.344 11 0.246 4 1.45 17

As would be expected, the correlation of Yards per Stop with these other measures is quite high. Offensive efficiency has a .975 correlation with Yards per Stop. The correlation of defensive efficiency with Yards per Stop is .974. These are nearly equivalent measures and the key difference between them has to do with the relative value of yards in different areas of the field.

Is Yards per Stop more palatable than offensive efficiency? It would certainly be easier to grasp for casual fans as an entry into some of the other analysis we’re doing at Football Outsiders. I think that was Chris’ primary motivation for suggesting it. I like the way it helps me visualize the way some teams move up and down the field with ease, as well as those that don’t.

And in that spirit, let’s take a look at the top offenses and defenses in 2013 according to Yards per Stop. All early-season sample size caveats apply here, but take a look at Baylor’s efficiency through this lens. You want to get the Bears offense off the field? So far in 2013, you have to give up nearly 300 yards first.

2013 Yards Per Stop - Top Offenses 2013 Yards Per Stop - Top Defenses
Rank Team Yds/Stop Rank Team Yds/Stop
1 Baylor 284.8 1 Michigan State 15.8
2 Navy 167.3 2 Maryland 15.9
3 Florida State 151.0 3 Arizona 18.7
4 UCLA 109.5 4 USC 18.8
5 Texas A&M 108.1 5 Florida 19.9
6 Central Florida 107.7 6 Louisville 20.8
7 Oregon 104.8 7 Oregon 21.0
8 Ohio State 98.8 8 Washington State 21.6
9 Louisville 93.3 9 Cincinnati 22.3
10 Wyoming 91.1 10 Miami 23.4

I’m not sure if I’ll be publishing Yards per Stop data with regularity throughout this season, but I’m interested in more feedback on it and any measures I do regularly publish. Feel free to offer suggestions in the comments below or via email.

FEI Week 4 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: Strength of schedule, based on the likelihood of an elite team going undefeated against the given team's entire 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.

These FEI ratings are a function of results of games played through September 21st. 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 Rk
FBS
MW
FBS
RMW
1 Oregon 2-0 .313 2 .439 2 .131 26 9.6 7.6
2 Alabama 3-0 .273 1 .288 8 .253 50 9.6 7.1
3 Stanford 3-0 .248 3 .224 12 .105 15 9.5 6.8
4 Oklahoma 3-0 .238 5 .212 13 .212 41 10.1 7.1
5 LSU 4-0 .227 4 .133 24 .080 10 8.0 4.5
6 Missouri 2-0 .223 23 .136 22 .184 35 8.7 6.9
7 Louisville 3-0 .221 6 .519 1 .608 112 10.1 7.2
8 Georgia 2-1 .216 8 .069 43 .103 14 7.8 5.5
9 Arizona 2-0 .208 15 .209 14 .129 25 8.4 6.4
10 Miami 2-0 .208 16 .154 18 .302 65 9.0 7.3
11 Ohio State 3-0 .207 9 .247 9 .382 80 9.2 6.3
12 Clemson 2-0 .202 10 .204 15 .270 53 7.6 6.3
Rk Team FBS
Rec
FEI LW GE GE
Rk
SOS Rk
FBS
MW
FBS
RMW
13 Florida State 2-0 .194 7 .406 4 .287 60 8.9 7.0
14 Georgia Tech 2-0 .188 30 .047 53 .183 34 7.0 5.4
15 UCLA 3-0 .181 27 .339 6 .038 3 7.8 5.2
16 Oklahoma State 2-0 .181 12 .232 10 .249 47 8.3 6.6
17 Washington 2-0 .178 14 -.037 72 .055 6 6.8 5.3
18 Mississippi 2-0 .175 11 .014 58 .119 19 7.3 5.9
19 Arizona State 1-1 .164 17 .077 41 .098 13 6.6 5.7
20 Florida 2-1 .164 18 .086 38 .077 8 6.5 4.4
21 Baylor 2-0 .161 28 .428 3 .222 43 8.1 6.1
22 Central Florida 3-0 .157 13 .344 5 .389 82 10.0 7.4
23 Texas Tech 3-0 .156 26 .225 11 .254 51 8.1 5.5
24 TCU 0-2 .153 24 .105 33 .109 17 7.0 6.3
25 Texas A&M 2-1 .148 19 .114 31 .105 16 6.9 4.7

Posted by: Brian Fremeau on 25 Sep 2013

11 comments, Last at 29 Sep 2013, 11:20pm by sinkerinthedirt

Comments

1
by BlueStarDude :: Wed, 09/25/2013 - 1:50pm

Like the yards per stop idea a lot.

2
by DSMok1 (not verified) :: Wed, 09/25/2013 - 2:27pm

I like the Yards/Stop idea a lot for its clarity--one question, though: what happens with field goals?

5
by Brian Fremeau :: Wed, 09/25/2013 - 3:30pm

I should have made that clear. In this study (per the reader suggestion), the only events that aren't stops are touchdowns. So all field goal attempts are stops, as are punts, interceptions, lost fumbles, safeties, turnovers on downs, and ends-of-half situations that aren't clock-kills.

7
by Aaron Brooks Go... :: Wed, 09/25/2013 - 3:51pm

I would propose that end-game FGs also shouldn't count as "stops".

3
by Adam H (not verified) :: Wed, 09/25/2013 - 2:45pm

Can someone explain to me why South Carolina is favored by 7 points at UCF, while Texas A&M is only favored by 3 at Arkansas? That makes no sense based on pretty much every objective (and subjective for that matter) rating system I've seen, including these.

I guess Arkansas has much better home field advantage than UCF.

Easy money? Or dangerous money?

4
by FrontRunningPhinsFan :: Wed, 09/25/2013 - 3:19pm

I don't know too much about college football compared to the NFL, but as an alumnus of UCF who still lives in Orlando, we don't have much of a home field advantage. We have a stadium for about 35,000 that never sells out.

Having said that, there is as much - if not more - excitement for this game as there was for the first game ever in the stadium against Texas, when Texas was #2 in the nation. I think Texas managed to win by a field goal at the end. The stadium will actually be loud for this game.

But in general, I'd say Arkansas has a MUCH better HFA by default. Just not in this game.

6
by Tino (not verified) :: Wed, 09/25/2013 - 3:33pm

The Texas A&M -3 at Arkansas line is apparently a hoax that has been spreading on the internet.

http://www.goodbullhunting.com/2013/9/23/4763624/about-that-a-m-at-arkan...

8
by AnonymousBoob (not verified) :: Wed, 09/25/2013 - 6:50pm

Vegasinsider shows that BetOnline released it a -3 and then took it down. As someone who used to use that site, I can attest that they sometimes released bat shit crazy lines early and then immediately dropped them. I never actually bet any of those lines, but I am guessing they do not honor them when they are way off (they didn't honor a Bowl prop on pass yards that was about 100 yards off).

So, I'm guessing Vegasinsider's feed saw an actual line, but that it was up for just a second and then removed before any action could take place.

With that said, using Sagarin's predictor gives you a line of -6.2, so it was off, but not exceptionally so.

I expect A&M to eventually open at about a 9/9.5.

9
by Brendan Scolari :: Thu, 09/26/2013 - 3:52pm

I really like the Yards per Stop idea for its simplicity and clarity. One nitpick though: it seems like it would tend to underrate offenses that tend to start with good field position (which usually means you have a good defense) and overrate offenses that tend to start with bad field position.

Basically, it becomes harder to gain yards the closer you get to the goalline. So the better your starting field position, the quicker and more often you get into redzone situations where it is tougher to gain yards (and coaches play more conservatively). The worse your average starting field position, the more "easy" yardage you can rack up before you get into those tough situations.

I'd think the effect would be compounded by the fact that teams with good defenses will tend to build leads and therefore play a conservative, clock-killing running offense that leads to shorter drives while teams with bad defenses will play from behind more often and therefore face more Prevent defenses.

Perhaps a YPS (Yards per Stop) and then a DYPS (Defense-Adjusted Yards Per Stop)? :)

10
by Anonymously (not verified) :: Thu, 09/26/2013 - 6:15pm

Love the Yards per Stop stat. Please keep it.

12
by sinkerinthedirt :: Sun, 09/29/2013 - 11:20pm

I'd be really interested in seeing this for coaches over a period of time.