Alabama-LSU unit matchups: efficiency ratings

To assess the statistical efficiency of each team's units for the upcoming clash in T-town, we're going to take a look at the S&P+ efficiency ratings, which measure the effectiveness of each and every (non-garbage-time) play in a college football game. The ratings basically combine two concepts that regular RBR readers are familiar with, and then adjusts for opponent strength.

The first concept is the success rate of each play in reaching a first down. This is the basis for the RB success rate that Todd compiles each week here at RBR. The second concept is the expected scoring value gained from each play by moving the ball to more favorable field position. This is the basis for the "value-added" numbers in my statistical efficiency posts each week. By combining these two concepts, the S&P system determines the value of each and every play made by an FBS offense or defense during the season (while the game is close), and then adjusts that value based on the strength of the opposing unit.

Below we'll take a look at how the offensive and defensive units for each team match up based on these ratings.

Alabama offense v. LSU defense

It should be no shock that LSU's defense ranks extremely high when it comes to efficiency ratings. They have been the second-most effective team at stopping opponents' running plays, and also second-most effective at stopping opponents' passing plays. Their overall efficiency as a unit is 2nd in college football only to Bama's.

However, as I pointed out earlier this week, the Tide's offense has been extremely efficient this season in its own right, ranking 3rd in overall efficiency behind only Wisconsin and Oregon. As the numbers show, the key to Bama's efficiency on offense this season has been its effectiveness on standard downs, or plays with down-and-distance that doesn't typically dictate a pass (i.e. 1st and 10, 2nd and 7, 3rd and 3, etc.). Teams that are successful at these plays typically avoid facing many passing downs, which are harder to convert.

The key takeaway from the battle between the Bama offense and the LSU defense has the be the high level of efficiency at which both units have been operating this season. Neither really has any weaknesses when it comes to the running game or the passing game, but it seems clear that the real strength of the Tide offense comes in its ability to have success on standard downs, which opens up both the running game and the passing game on ensuing plays. A major key will no doubt be LSU's defense, which ranks 3rd in standard down efficiency, finding ways to limit the effectiveness of the Bama offense on those plays.

LSU offense v. Alabama defense

As we've established here before, the Tide defense is the most efficient unit in the nation. Much like the Bama offense, the Tide defense builds its success around its effectiveness on standard downs and running plays, where it ranks 1st in college football. The Tide is also extremely effective when facing passing downs, but ranks *only* 14th when it comes to defending pass plays, indicating that when the Tide has given up big passing plays, they haven't come on obvious passing downs (see opening drive of Florida and Ole Miss games).

LSU's offense meanwhile has been good, but not quite truly on the elite level when it comes to play-by-play efficiency, ranking 15th nationally. While they have had success with their running game, a fair share of their running plays have been unsuccessful, and as a result they have had a little more difficulty on standard downs than the Bama offense. Perhaps a bit surprisingly, they have actually been more efficient (relative to other offenses) on passing plays and in obvious passing situations. So while many consider LSU a running offense, they have actually been even more effective in their passing game.

On the surface it appears that Alabama has an advantage in this matchup, and the efficiency ratings would suggest that may be the case. However, LSU does hold an advantage on passing plays efficiency (but not passing downs efficiency), indicating the LSU offense's key advantage may be passing plays on standard downs. This makes sense for those who have watched Bama this season, as the only real cracks in the Tide's defensive armor have come on just such plays: pass attempts on 1st and 2nd downs.

Alabama special teams v. LSU special teams

The FEI efficiency ratings, which measure the efficiency of each possession (rather than play), award value to special teams units for adding value to their teams at the beginning or end of each possession. Just when you thought it was all crimson roses, here comes your ticket back to earth. LSU has been the most effective team in the nation at producing value from their special teams. Bama, meanwhile, is in the middle of the pack in FBS.

Granted, special teams don't typically add as much value during the course of the game as the offensive and defensive units, but they can and do most certainly affect the outcomes of games in real ways, and considering both how closely the two offenses and defenses match up and just how wide the gap is between the effectiveness of the two special teams units, there is certainly a very real advantage here for the Tigers, and one that could easily alter the outcome of the game.