by Brian Fremeau

The Fremeau Efficiency Index principles and methodology 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 from a privileged perspective (explained here) and represents the likelihood that an Elite team (top 5) would post an undefeated record against the given team's opponents to date.

Projected outcomes are not included in the following FEI ratings. The ratings are calculated based on data from all FBS games played through Saturday, October 18. Only games between FBS teams are considered.

The Week 8 FEI Ratings for all 120 FBS teams can be found here. Expanded FEI Ratings data can be found here.

Offensive and Defensive Efficiency

As my FO colleague Bill Connelly has addressed this season in his weekly Varsity Numbers columns, traditional stats in college football can be particularly misleading if not examined in the proper context. The NCAA ranks each team in "Total Offense" and "Total Defense" simply by yards earned and allowed per game. If every team began every possession from their own 30-yard line, played the same number of possessions per game as everyone else, never played a garbage-time possession, and faced the same opponent as every other team on every down, then yards per game would be a fine way to rank offenses and defenses.

FEI was built as a drive-based system for two main reasons. The first was practical: College football play-by-play data was too massive to collect, too unreliable, or in some cases several years back, too unavailable. The second reason was philosophical: Drives are essential and fundamental in football, a game played in alternating possessions that gives teams equal opportunity to score and be scored upon. Game Efficiency, therefore, is the starting point for FEI, a measure of the collective success of a team maximizing its own possessions and minimizing those of its opponent. But what about breaking that success down by unit efficiency standards? We'll start with offense and defense. We'll take a closer look at special teams and field position efficiency next week.

To measure a team's Offensive Efficiency in each game, I first discarded clock-kill and garbage-time possessions. Second, I measured the offensive scoring expectation of a team from each drive's starting field position according to national baselines. Third, I modified the actual result of non-touchdown drives to account for national punting/kicking averages (the opponent's 12-yard line is worth 2.528 points offensively regardless of the success of the field goal attempt; the opponent's 35-yard line is worth 0.810 points offensively regardless of a field goal or punt), and credited touchdown-scoring drives with 6.958 points (the average touchdown value neutralized for average rates of point-after and two-point conversion attempts). Offensive Efficiency (OE) represents the sum of the value of offensive points earned divided by the sum of its offensive score expectations over the drives of the game, minus one (to calibrate OE as a zero-sum measurement). Defensive Efficiency (DE) is equal to the opponent's OE.

For example, on October 11, Texas defeated Oklahoma in the Red River Rivalry 45-35 in 24 total possessions. The final two possessions of the game, following Oklahoma's turnover on downs with 2:31 left in the game, were discarded as garbage-time possessions.

Both offenses played very efficiently, scoring well over national average expectations. In a vacuum, Texas' offense outplayed Oklahoma's. To date over the course of the season, Texas' average OE is second only to Tulsa's and Oklahoma ranks third. But how do we adjust these results for the level of competition faced? Is the Longhorns' defense good, bad or average?

Texas' stifling defense didn't just show up last weekend against Missouri. Every Texas opponent to date, including Oklahoma and their five-touchdown day in the Cotton Bowl, has been held far below its average Offensive Efficiency against the Longhorns. Clearly, OE and DE need to be adjusted to account for the quality of the opposition faced.

Adjusted Offensive Efficiency (AOE) and Adjusted Defensive Efficiency (ADE) are the opponent-adjusted values of OE and DE. Like FEI, the multiple-order adjustments are weighted according to both the strength of the opponent and the relative significance of the result; efficiency against a team's best competition faced is given more relevance weight. AOE and ADE represent a team's value over/under average. Positive AOE and negative ADE are the most valuable.

Offensive and Defensive Efficiency data for all teams can be found in the FEI Expanded Ratings here.

Texas is the only team currently rated in the top ten in both AOE and ADE. Alabama is on the doorstep (No. 11 AOE, No. 1 ADE). Penn State, Florida, and USC currently rank in the top 20 in AOE and ADE. Texas' upcoming undefeated opponent Oklahoma State rates stronger in ADE than AOE, a reversal of its traditional-stat rankings (NCAA Ranks: No. 7 Total Offense, No. 47 Total Defense). Like Texas, the Cowboys held down Chase Daniel and Missouri and kept their other opponent offenses largely in check. Will Oklahoma State present the most formidable challenge yet to Colt McCoy's Burnt October Heisman campaign? Can Ohio State shut down Penn State's offensive juggernaut in Columbus, or are the Nittany Lions capable of a USC-like offensive outburst? Is the showdown between Georgia's offense and LSU's defense actually a mismatch? I'll take a closer look at past season AOE and ADE trends in the coming weeks.

Posted by: Brian Fremeau on 22 Oct 2008

10 comments, Last at 23 Oct 2008, 2:08pm by T-Diddy