Possibly the closest Super Bowl matchup in history also poses the question: how much does it mean when certain aspects of an NFL team improve dramatically in the second half of the season?
20 Nov 2013
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|
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|
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|
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.
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.
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.
4 comments, Last at 22 Nov 2013, 5:21am by Brian Fremeau