by Brian Fremeau
There are a number of ways I slice possession data in order to evaluate team efficiency. The top offenses typically rise to the top of most, if not all categories. Alabama currently leads the nation in opponent-adjusted OFEI possession efficiency, unadjusted possession efficiency, touchdown rate (reaching the end zone on 60% of its non-garbage drives to date), and available yards percentage (earning 73.8% of drive yards based on starting field position). The Crimson Tide also rank second nationally in first down rate (earning at least one first down on 87.1% of non-garbage drives), second nationally in explosive drive rate (35.7% of Alabama drives average at least 10 yards per play), third in busted drive rate (only 2.9% of drives gain zero or negative yards), and fourth in turnover rate (only 4.3% of drives have resulted in an interception or fumble).
On defense, Clemson has a similarly dominant efficiency profile. The Tigers rank first nationally in opponent-adjusted possession efficiency, unadjusted possession efficiency, first down rate (53.4%), and available yards percentage (22.4%). They rank second in touchdown rate (6.8%), eighth in busted drive rate (18.2%), 11th in turnover rate (17.0%), and 20th in explosive drive rate (8.0%).
Each of those efficiency measures are descriptive in some way as to how well Alabama's offense and Clemson's defense maximizes their possessions. Moving the ball effectively and consistently down the field and into scoring range on offense, and keeping an opponent from doing the same when they have the ball, are the basic elements of winning football games. Win offensive and defensive possessions, and win the game more often than not.
Miami defeated Florida State on Saturday by a final score of 27-10 and had a solid available yards percentage margin on the day. The Hurricanes earned 41.5% of available yards on offense, and held Florida State to only 18.0% of available yards. I charted all FBS games played in 2019 to calculate the relationship between margin of victory and available yards percentage margin. Miami's 23.5% margin and 17-point victory falls right along the best fit trendline.
Week 10 featured several key outliers on this chart as well. Notre Dame had a similarly strong edge over Virginia Tech as Miami had over Florida State. The Fighting Irish earned 49.4% of available yards and allowed only 26.6%, a margin of 22.8%. Instead of winning by several scores, however, Notre Dame needed a late touchdown to eke out a one-point victory over the Hokies. Available yards percentages account for the success of an Irish second-quarter drive to the Virginia Tech 2-yard line, but don't account for the fumble and 98-yard touchdown return that the Hokies defense scored at the conclusion of that drive.
Cincinnati posted a 46-43 victory over East Carolina with an available yards percentage margin deficit of 20.0% -- the Bearcats earned only 50.6% of available yards and surrendered a whopping 70.6% of available yards to the Pirates. East Carolina ended each of its last 11 offensive possessions in the game in plus-territory, but also gave up a costly pick-six while clinging to a fourth-quarter lead. No team has been victorious this year with a greater available yards percentage deficit than Cincinnati.
Less dramatically in terms of final score, but no less dramatic in terms of the relationship between available yards margin and margin of victory, was Oregon's blowout win over USC. The Ducks crushed the Trojans by a final score of 56-24, with a non-garbage final score of 42-17. That 25-point non-garbage victory featured two Oregon non-offensive touchdowns -- an interception return and kickoff return in the second quarter. USC had three failed trips in non-garbage time into Oregon territory, and two offensive opportunities that ended inside the Oregon 10-yard line that didn't reach the end zone. USC edged Oregon in available yards percentage by 1.9%, but still lost by more than three scores. No other result this season is plotted further from the best fit trendline in the chart.
Special teams and defensive scores played a big part in each of these outlier cases. Though those events had a big impact on the final outcome of these games, they aren't the kind of repeatable events that inform the FEI ratings. Available yards percentage, and other reliable offensive and defensive efficiency metrics detailed in the FEI ratings pages, tell a more predictive story of the respective strengths of each team.
2019 FEI Ratings (through Week 10)
The Fremeau Efficiency Index (FEI) is a college football rating system based on opponent-adjusted possession efficiency, representing the per possession scoring advantage a team would be expected to have on a neutral field against an average opponent. Unadjusted possession efficiency (PE) is calculated as a function of offensive, defensive, and special teams game splits. Schedule strength is represented by each team's average per possession opponent adjustment (OA). Opponent-adjusted offense ratings (OFEI), opponent-adjusted defense ratings (DFEI), and opponent-adjusted special teams ratings (SFEI) are calculated in a similar manner as overall FEI ratings. Team records against all FBS opponents (W-L) and against opponents ranked in the FEI top 10 (v10), top 20 (v20), top 30 (v30), top 40 (v40), and top 50 (v50) are also provided.
Ratings and supporting data are calculated from the results of non-garbage possessions in FBS vs. FBS games.