Degrees of Greatness: A Statistical Comparison of the 2009, 2011 and 2012 Defenses

'I'd think there are degrees of greatness,' Adam said.

'I don't think so,' said Samuel. 'That would be like saying there is a little bigness. No. I believe when you come to that responsibility the hugeness and you are alone to make your choice. On one side you have warmth and companionship and sweet understanding, and on the other - cold, lonely greatness. There you make your choice."

― John Steinbeck, East of Eden

First up: raw stats. Again, all stats taken from www.cfbstats.com. If you find any errors, please point them out so I can correct them. Blog to a standard.

Tl;dr version: our 2009 defense was great, our 2012 defense was great, and our 2011 defense was greater.


SCORING DEFENSE
Points per game:

2009: 11.7 ppg, #2 in the country (1.3 ppg behind Nebraska)
2011: 8.2 ppg, #1 in the country (3.1 ppg ahead of LSU)
2012: 10.9 ppg, #1 in the country (1.9 ppg ahead of Notre Dame)

Perspective: www.cfbstats.com lists stats since 2007. Looking at all teams since 2007, 2011 Alabama’s defense allowed 0.8 ppg less than the second-best scoring defense during that timespan, 2008 USCw.

Since 2007, there have been 128 teams that surrendered, on average, 4+ times as many points per game as the 2011 Alabama defense. (I had originally written that as "as many points per quarter as the 2011 Alabama defense gave up per game," but then realized that overtime would probably render that an inaccurate statement.) Of those 128 teams, only one was in the SEC: 2012 Tennessee allowed 35.7 ppg. (2009 Texas A&M gave up 33.5 ppg, but were not yet in the SEC.)

Since 2007, there have been 14 teams that gave up 5+ times as many points per game as the 2011 Alabama Defense.


TOTAL DEFENSE
Yards per game:

2009: 245.4 ypg, #2 in the country (5.7 ypg behind TCU)
2011: 183.6 ypg, #1 in the country (77.9 ypg ahead of LSU)
2012: 250.0 ypg, #1 in the country (3.8 ypg ahead of FSU)

Perspective: Since 2007, the 2011 Alabama defense had the best total defense (yards per game), allowing 34.2 fewer yards per game than #2 2008 TCU.

In 2011, Alabama allowed 183.6 ypg. If you double that, it gives you 367.2 yards per game. 367.2 ypg would have ranked:

2007: #50/119 (ahead of USCe, Mizzou, Kentucky, Tennessee, TAMU, and Ole Miss.
2008: #68/120 (ahead of Arkansas, Mizzou, and TAMU)
2009: #59/120 (1.2 ypg behind #58 Mississippi State, and ahead of Mizzou, the Auburnite, Arkansas, and TAMU)
2010: #59/120 (tied with Fresno State, and ahead of the Auburnite, Tennessee, Ole Miss, and Vandy)
2011: #52/120 (ahead of Kentucky, TAMU, Mizzou, the Auburnite, and Ole Miss)
2012: #38/124 (ahead of Ole Miss, Mississippi State [#webelieve], TAMU, Mizzou, Kentucky, Arkansas, the Auburnite, and Tennessee)


TOTAL DEFENSE
Yards per play:

2009: 4.08 ypp, #4 in the country (0.24 ypp behind #1 Texas)
2011: 3.32 ypp, #1 in the country (0.76 ypp ahead of #2 LSU)
2012: 4.18 ypp, #2 in the country (0.33 ypp behind #1 FSU)

Perspective: Since 2007, the 2011 Alabama defense allowed the fewest yards per play, allowing 0.29 fewer yards per play than #2 2008 USCw.


PASSING DEFENSE
Passing yards per game:

2009: 166.0 ypg, #10 in the country (15.9 ypg behind #1 Eastern Michigan, 14.1 ypg behind #2 Florida, 3.0 ypg more than #8 South Carolina, and 1.1 ypg more than #9 Vandy)
2011: 111.5 ypg, #1 in the country (20.2 ypg better than #2 South Carolina)
2012: 173.6 ypg, #7 in the country (11.7 ypg behind #1 FSU)

Perspective: Since 2007, the 2011 Alabama defense allowed the fewest passing yards per game, allowing 17.3 fewer yards per game than #2 2010 TCU.


PASSING DEFENSE
Passing yards per attempt:

2009: 5.2 ypa, #2 in the country (tied with Iowa and TCU, 0.1 ypa behind #1 Nebraska)
2011: 4.3 ypa, #1 in the country (0.6 ypa better than #2 South Carolina. LSU was #3, Georgia was #4, Penn State was #5, and Mississippi State was tied for #6)
2012: 6.1 ypa, #16 in the country (tied with Pitt, Va. Tech, Northern Illinois, and Stanford, and 1.1 ypa behind #1 FSU)

Perspective: Since 2007, 2011 Alabama has the best passing defense (yards per attempt), allowing 0.3 fewer yards per pass attempt than #2 2008 USCw.


PASSING DEFENSE
Passer Efficiency Rating:

2009: 87.65, #2 in the country (0.41 behind #1 Nebraska)
2011: 83.69, #1 in the country (10.53 better than #2 USCe)
2012: 103.67, #7 in the country (8.25 behind #1 FSU, 8.19 behind #2 Florida, 1.23 behind #6 Vandy)

Perspective: Since 2007, 2011 Alabama has the best passing defense (passer efficiency rating), 2.04 better than #2 2008 USCw.


RUSHING DEFENSE
Rushing yards per game:

2009: 79.36 ypg, #2 in the country (7.0 ypg behind #1 Texas)
2011: 72.15 ypg, #1 in the country (10.54 ypg ahead of #2 FSU)
2012: 76.36 ypg, #1 in the country (10.56 ypg ahead of #2 BYU)

Perspective: Since 2007, our 2011 rushing defense (yards per game) is #3, 1.46 yards per game behind #2 2007 Oregon State, and 25.07 ypg behind #1 2008 TCU. [This doesn’t appear to be a typo: the 2008 TCU rush defense allowed 612 yards on 355 carries over 13 games, for 1.72 ypc and 47.08 ypg.]


RUSHING DEFENSE
Rushing yards per carry:

2009: 2.83 ypc, #6 in the country (tied with North Carolina, and 0.62 ypc behind #1 Texas)
2011: 2.43 ypc, #2 in the country (0.08 ypc behind #1 FSU)
2012: 2.43 ypc, #1 in the country (0.3 ypc ahead of #2 UConn)

Perspective: Since 2007, the 2011 and 2012 rush defense (yards per carry) are tied for #6, 0.71 ypc behind #1 2008 TCU.


APPLES TO APPLES

Compared to our 2011 defense, the 2009 defense allowed 3.5 more points per game, 61.8 more yards per game, 0.76 more yards per play, 54.5 more passing yards per game, 0.9 more passing yards per attempt, a 3.96 point higher passer rating, 7.21 more rushing yards per game, and 0.4 more rushing yards per carry.

Compared to our 2011 defense, this year’s defense allowed 2.7 more points per game, 66.4 more yards per game, 0.86 more yards per play, 62.1 more passing yards per game, 1.8 more passing yards per attempt, a 19.98 point higher passer rating, 4.21 more rushing yards per game, and the same rushing yards per carry (to two significant figures).

Comparing the 2009 defense to the 2012 defense: the 2009 unit allowed 0.8 more points per game, 3.03 more rushing yards per game, and 0.4 more yards per carry, while the 2012 defense allowed 4.6 more yards per game, 0.1 more yards per play, 7.6 more passing yards per game, 0.9 more passing yards per attempt, and a 16.02 point higher passer rating.


ADVANCED STATS

I’m going to run through these relatively quickly. I can go into greater detail if requested, but I’m not sure what there is to add. All advanced stats are taken from www.footballoutsiders.com.

FEI:

"The Fremeau Efficiency Index (FEI) considers each of the nearly 20,000 possessions every season in major college football. All drives are filtered to eliminate first-half clock-kills and end-of-game garbage drives and scores. A scoring rate analysis of the remaining possessions then determines the baseline possession efficiency expectations against which each team is measured. A team is rewarded for playing well against good teams, win or lose, and is punished more severely for playing poorly against bad teams than it is rewarded for playing well against bad teams.

"DFEI: Defensive FEI, the opponent-adjusted efficiency of the given team's defense."

- http://www.footballoutsiders.com/stats/feidef2012

2009: -.753, #1 in the country
2011: -.780, #1 in the country
2012: -.657, #4 in the country (behind Florida, Michigan State and Stanford)

Perspective: The FEI Defensive ratings are listed since 2007. Since that time, their top five are:

1: 2012 Florida (-.795)
2: 2011 Alabama (-.780)
3: 2009 Alabama (-.753)
4: 2011 LSU (-.747)
5: 2009 Iowa (-.742)

S&P+:

"The S&P+ Ratings are a college football ratings system derived from the play-by-play data of all 800+ of a season's FBS college football games (and 140,000+ plays).
There are three key components to the S&P+:
• Success Rate: A common Football Outsiders tool used to measure efficiency by determining whether every play of a given game was successful or not. The terms of success in college football: 50 percent of necessary yardage on first down, 70 percent on second down, and 100 percent on third and fourth down.
• EqPts Per Play (PPP): An explosiveness measure derived from determining the point value of every yard line (based on the expected number of points an offense could expect to score from that yard line) and, therefore, every play of a given game.
• Opponent adjustments: Success Rate and PPP combine to form S&P, an OPS-like measure for football. Then each team's S&P output for a given category (Rushing/Passing on either Standard Downs or Passing Downs) is compared to the expected output based upon their opponents and their opponents' opponents. This is a schedule-based adjustment designed to reward tougher schedules and punish weaker ones.

The S&P+ figures used in the tables below only look at the plays that took place while a game was deemed "close," or competitive. The criteria for being "close" are as follows: a game within 24 points in the first quarter, with 21 points in the second quarter, and within 16 points in the second half."

- http://www.footballoutsiders.com/stats/ncaadef2012

2009: 151.5, #1 in the country
2011: 179.7, #1 in the country
2012: 154.3, #1 in the country (although the website actually lists "Off. S&P+," I believe this to be a typo)

Perspective: The S&P+ Defensive ratings are listed since 2005. In that time, their top five are:

1: 2011 Alabama (179.7)
2: 2008 TCU (165.8)
3: 2011 LSU (159.6)
4: 2012 Alabama (154.3)
5: 2009 Alabama (151.5)


INTERESTING FACT:

Tennessee allowed five more points this year (428) than Alabama did in our most recent three National Championship seasons combined (423; 164 in 2009, 106 in 2011, and 153 in 2012).