In 2008 we investigated USC's defense in order to rank it among the best defenses of all-time. Now let's do the same for Alabama.
First off, let's forget about calling Alabama the best defense of all-time. It's too hard to compare defenses from early college football to those of today in any practical way, given that you had teams like 1891 Yale:
9/30 vs. Wesleyan (2-7) W 28-0
10/3 vs. Crescent A.C. (non-IA) W 26-0
10/7 @ Trinity (Conn) (6-4) W 36-0
10/10 vs. Williams (8-2-1) W 46-0
10/14 vs. Springfield (5-8-1) W 28-0
10/24 vs. Orange A.C. (non-IA) W 36-0
10/31 vs. Lehigh (7-6) W 38-0
11/3 vs. Crescent A.C. (non-IA) W 70-0
11/7 vs. Wesleyan (2-7) W 76-0
11/11 vs. Amherst (8-4-3) W 27-0
11/14 vs. Pennsylvania (11-2) W 48-0
11/21 vs. Harvard (13-1) W 10-0
11/26 vs. Princeton (12-1) W 19-0
which is kind of hard to judge. So we'll stick to the modern era for the most part.
Alabama finished 2011 with easily the best defense, by adjusted scoring defense, and both rushing and passing defense per-game and per-play when adjusted for their opposition.
Scoring defense rankings:
raw adj Team rec Offense Defense
1 1. Alabama 12-1 40.94 [ 9] 5.81 [ 1]
2 2. LSU 13-1 40.62 [ 12] 8.14 [ 2]
5 3. Penn State 9-4 22.48 [ 91] 13.06 [ 3]
4 4. Florida St 9-4 29.20 [ 45] 16.00 [ 4]
25 5. Stanford 11-2 43.07 [ 6] 16.08 [ 5]
Total defense (yards per game, adjusted for opponents; note rushing, passing rank also)
Raw Adj Team Rec Total[rank] Rush[rank] Pass[rank]
1 1. Alabama 12-1 193.1[ 1] 42.3[ 1] 150.7[ 1]
11 2. Texas 8-5 250.2[ 2] 75.6[ 4] 174.6[ 7]
2 3. LSU 13-1 257.4[ 3] 75.0[ 3] 182.3[ 10]
3 4. South Carolina 11-2 264.3[ 4] 111.1[ 14] 153.2[ 2]
6 5. Michigan St 11-3 266.6[ 5] 74.8[ 2] 191.8[ 16]
Top per-carry rushing defenses, adjusted for opponents; note total yardage and passing rank
Rank Team Rec Total[rank] Rush[rank] Pass[rank]
1. Alabama 12-1 7.1[ 1] 2.2[ 1] 4.8[ 1]
2. Michigan St 11-3 8.4[ 5] 2.3[ 2] 6.0[ 12]
3. Texas A&M 7-6 8.9[ 8] 2.4[ 3] 6.5[ 26]
4. Florida St 9-4 9.0[ 10] 2.6[ 4] 6.4[ 23]
5. LSU 13-1 8.0[ 2] 2.6[ 5] 5.3[ 4]
So in just about every relevant category, Alabama was the #1 team on defense this year. Since scoring defense is the stat we have going back as far as we want (thanks to James Howell's College Football Scores), we'll use that. In 2008 when we looked at USC's defense, we came up with this chart (mislabeled as "top offenses" oh well).
Top defenses 1980-2008 seasons (standardized for year played)
# year Team rec adj. ave year's ave difference
1. 1985 Michigan 10-1-1 1.87 [ 1] 22.26 20.39
2. 2008 Southern Cal 12-1 6.71 [ 1] 26.34 19.63
3. 2000 Florida State 11-2 6.54 [ 1] 25.74 19.20
4. 1991 Miami FL 12-0 3.87 [ 1] 23.04 19.17
5t 2001 Miami FL 12-0 7.54 [ 1] 26.56 19.02
5t 2005 Ohio State 10-2 7.26 [ 1] 26.28 19.02
7. 1996 Ohio State 11-1 6.60 [ 1] 25.46 18.86
8. 1988 Miami FL 11-1 4.84 [ 1] 23.66 18.82
9. 2003 Louisiana State 13-1 7.74 [ 1] 26.24 18.50
10. 1991 Washington 12-0 4.56 [ 2] 23.04 18.48
The 1985 Michigan team gave up 8.2 points per game, but faced seven top 25 offenses: #1 Iowa, #5 Nebraska, #12 Maryland, #18 Ohio State, #19 Purdue, #24 Illinois, and #25 Notre Dame. They had 3 shutouts and held 7 opponents to single digits. They held Iowa (36.7 average) to 12 points.
When we add Alabama of 2011 into the mix (and add all teams from 2009 to 2011) we get this:
# year Team rec adj. ave year's ave difference
1. 2011 Alabama 12-1 6.07 [ 1] 27.49 21.42
2. 1985 Michigan 10-1-1 1.87 [ 1] 22.26 20.39
3. 2008 Southern Cal 12-1 6.71 [ 1] 26.34 19.63
4. 2011 LSU 13-1 8.13 [ 2] 27.49 19.36
5. 2009 Alabama 14-0 6.92 [ 1] 26.16 19.24
6. 2000 Florida State 11-2 6.54 [ 1] 25.74 19.20
7. 1991 Miami FL 12-0 3.87 [ 1] 23.04 19.17
8t 2001 Miami FL 12-0 7.54 [ 1] 26.56 19.02
9t 2005 Ohio State 10-2 7.26 [ 1] 26.28 19.02
10. 1996 Ohio State 11-1 6.60 [ 1] 25.46 18.86
We have three new entries to the 1980+ top defenses. First, Alabama's 2009 national championship made the list at #3, but was knocked back to #5 by this year's squad as well as this season's LSU team, which had a defense about as good as the 2009 Alabama team. The 2011 Alabama team takes the #1 spot. Our numbers are a bit different here as we have included overtime scores, since that's what our 1996+ data contains. Some day we'll make a version that removes overtime scoring, but it doesn't affect the "difference" column very much.
This year's Alabama team, like 1985 Michgan, gave up 8.2 points per game. They held 8 of 13 opponents to single digits, recording 3 shutouts, including the 21-0 win over LSU in the national championship game. Adjusted for their schedule they gave up 6.07 points, which is 21.42 lower than the average score for a game in the 2011 season.
Just for fun, let's keep going back in time by decades (or more):
1970+
# year Team rec adj. ave year's ave difference
1. 1972 Oklahoma 11-1 -1.12 [ 1] 20.48 21.60
2. 2011 Alabama 12-1 6.07 [ 1] 27.49 21.42
3. 1985 Michigan 10-1-1 1.87 [ 1] 22.26 20.39
4. 1973 Nebraska 9-2-1 1.15 [ 1] 20.86 19.71
5. 2008 Southern Cal 12-1 6.71 [ 1] 26.34 19.63
6. 1972 Nebraska 9-2-1 1.09 [ 2] 20.48 19.39
7. 2011 LSU 13-1 8.13 [ 2] 27.49 19.36
8. 2009 Alabama 14-0 6.92 [ 1] 26.16 19.24
9. 2000 Florida State 11-2 6.54 [ 1] 25.74 19.20
10. 1973 Ohio State 10-0-1 1.68 [ 2] 20.86 19.18+
1970's teams from Nebraska, Ohio State, and Oklahoma push out all of the teams from the 1990s, but Alabama of 2011 is still in 2nd place. 1972 Oklahoma takes over at #1, and introduces the first "negative" defensive average. What does this mean? Remember, this is based on who they played. The Sooners in 1971 held their opponents, per-game, to 21.6 points lower than their average score. The average team score, overall, was 20.48, so that average team would score -1.12 points against Oklahoma. In other words, it takes an above average effort to avoid a shutout against the 1972 Sooners. In actuality, they shut out 4 of their 12 opponents and held 5 more to single digits. Since they played a very tough schedule (that is, against tough offenses) their defensive average went "negative."
1950+
# year Team rec adj. ave year's ave difference
1. 1952 USC 10-1 -3.73 [ 1] 18.33 22.06
2. 1972 Oklahoma 11-1 -1.12 [ 1] 20.48 21.60
3. 2011 Alabama 12-1 6.07 [ 1] 27.49 21.42
4. 1985 Michigan 10-1-1 1.87 [ 1] 22.26 20.39
5. 1950 Illinois 7-2 -0.85 [ 1] 19.25 20.10
6. 1973 Nebraska 9-2-1 1.15 [ 1] 20.86 19.71
7. 1952 Tennessee 8-2-1 -1.37 [ 2] 18.33 19.70
8. 2008 Southern Cal 12-1 6.71 [ 1] 26.34 19.63
9. 1972 Nebraska 9-2-1 1.09 [ 2] 20.48 19.39
10. 2011 LSU 13-1 8.13 [ 2] 27.49 19.36
Now the "negatives" start to proliferate as teams from the 1950s are introduced. Their was less parity then so the top defenses could really dominate. The 1960s featured slightly lower scoring so it was harder for teams to make the list (lower scoring average means less opportunity to go below that average). 1952's USC team held 10 of their 11 foes to single digits and racked up 5 shutouts.
1940+
# year Team rec adj. ave year's ave difference
1. 1945 Army 9-0 -9.04 [ 1] 16.35 25.39
2. 1945 Navy 7-1-1 -7.48 [ 2] 16.35 23.83
3. 1944 March Field 7-2-2 -6.11 [ 1] 17.08 23.19
4. 1946 Notre Dame 8-0-1 -6.74 [ 1] 16.13 22.87
5. 1949 Michigan 6-2-1 -2.53 [ 1] 20.01 22.54
6. 1952 USC 10-1 -3.73 [ 1] 18.33 22.06
7. 1943 Notre Dame 9-1 -5.64 [ 1] 16.36 22.00
8. 1943 Northwestern 6-2 -5.60 [ 2] 16.36 21.96
9. 1949 Notre Dame 10-0 -1.37 [ 2] 20.01 21.38
10. 1972 Oklahoma 11-1 -1.12 [ 1] 20.48 21.60
Include the years of WWII and just after and those teams take over the entire list. The only post early-50s team on the list is the 1972 Oklahoma squad. The great 1945 Army team tops the list, holding their opponents to 25.39 points lower than their normal tally. They had 5 shutouts in 9 games.
1915+
# year Team rec adj. ave year's ave difference
1. 1918 Great Lakes Navy 6-0-2 -12.23 [ 1] 14.05 26.28
2. 1945 Army 9-0 -9.04 [ 1] 16.35 25.39
3. 1917 Wash & Jeff 7-3 -10.12 [ 1] 15.14 25.26
4. 1917 Ohio State 8-0-1 -9.40 [ 2] 15.14 24.54
5. 1918 Illinois 5-2 -10.46 [ 2] 14.05 24.51
6. 1945 Navy 7-1-1 -7.48 [ 2] 16.35 23.83
7. 1918 Texas A&M 6-1 -9.53 [ 3] 14.05 23.59
8. 1944 March Field 7-2-2 -6.11 [ 1] 17.08 23.19
9. 1917 Notre Dame 6-1-1 -7.80 [ 3] 15.14 22.94
10. 1946 Notre Dame 8-0-1 -6.74 [ 1] 16.13 22.87
Going back to WWI, now we see just teams from the two war eras. This was a time of great disparity in college football as many players were off to war, and there was a great concentration of young men in places like Great Lakes Navy, many of whom had already played college football before joining the armed forces. Great Lakes Navy recorded 5 shutouts in 8 games, including a 17-0 win over Mare Island Marines in the 1919 Rose Bowl.
1869+
# year Team rec adj. ave year's ave difference
1. 1885 Yale 7-1 -6.09 [ 1] 26.07 32.16
2. 1887 Yale 9-0 -7.04 [ 1] 20.59 27.63
3. 1886 Princeton 7-0-1 -6.51 [ 1] 21.06 27.57
4. 1918 Great Lakes Navy 6-0-2 -12.23 [ 1] 14.05 26.28
5. 1914 Harvard 7-0-2 -9.98 [ 1] 15.68 25.66
6. 1885 Princeton 9-0 0.58 [ 2] 26.07 25.49
7. 1945 Army 9-0 -9.04 [ 1] 16.35 25.39
8. 1917 Wash & Jeff 7-3 -10.12 [ 1] 15.14 25.26
9. 1913 Princeton 5-2-1 -9.62 [ 1] 15.08 24.70
10. 1917 Ohio State 8-0-1 -9.40 [ 2] 15.14 24.54
When we go "all-time", Yale is #1 as expected. But it's not the Yale team from 1891 that we featured at the top of the post! Even though that team allowed no points the entire season, they didn't really play a tough schedule overall, and there wasn't enough scoring that year for them to make the list. Even though a team's "corrected" scoring defense can be an average number, the actual game scores can't go negative, which was what Yale would have needed to do in 1891 to make the list. Here's what their line looked like:
year Team rec adj. ave year's ave difference
1891 Yale 13-0 -3.59 [ 1] 16.25 19.84
So they held their average opponent to 19.84 points below their normal tally—which was the best they could do, since they shut out every opponent!
The Yale team that tops the list, from 1885, allowed 11 points total (1.375 per game) which was 32 points lower than the average of the teams they played. They shut out 6 of 8 opponents.
1885 was a high-scoring year, coming just a few years after scoring took a huge leap in 1883 with a new point system. Prior to that, scoring was more similar to soccer (the average in 1882 was 5.6 points TOTAL per game). That's getting into the era when the game was more of a soccer/rugby hybrid, though in the late 1880s the game still owed more to rugby than what we know as football today, as they were still a few decades away from the first forward pass.
So our verdict on Alabama is: best defense in college football in the last three decades; 2nd best since 1970 (or 1960), and 3rd best since 1950. And beyond that, the comparisons become sort of ridiculous; in terms of players, playing style, equipment, and everything else, it's truly a different era.
Just curious, where does 1901 Michigan fit and why is it so far out of first?
The Wolverines won their games 550-0 that season with Yost's point a minute offense. On a possession basis, their opponents saw the ball much more frequently than a lot of these top 1869+ defenses that were in 6-0 and 9-0 games. Any explanation?
Thanks.
Posted by: Adam | January 11, 2012 at 12:47 PM
Good question, Adam
1- like we said, the further you go back, the less sense it makes to compare teams to today's. Or even, for that era, because interplay between east and western teams wasn't common
2- Michigan's schedule was not that hard...they played Albion, Case, Buffalo (128-0), Oberlin, and Ohio State and Stanford, all of whom are not considered "I-A" by Howell's data. Not sure why OSU and Stanford aren't but that leaves Indiana, Northwestern, Carlisle, Chicago, Beloit, and Iowa as opponents.
A team's defensive rating can only as low as the average of their opponents offensive average—-they can do this by shutting out every opponent. Michigan's opponents averaged (these are adjusted values too based on defenses):
Indiana 19.7
Northwestern 15.8
Carlisle 8.03
Chicago 7.78
Beloit 12.35
Iowa 15.2
So Michigan has a defense that holds its opponents to roughly 13.1 points below average, compared to the 20s and 30s on the teams high in the charts. Their expected yield against the average I-A team was 0.89 points, despite giving up none the whole year.
So basically, Michigan didn't play teams that scored enough, to be able to undercut their scores enough by shutting them out! It's why no team from before 1893 can show up, when the averages were 5 points per game.
Not only does 1901 Michigan not make the list, they are only #4 that year on defense! That's another problem: when dealing with offense, where the sky's the limit, you can always get a comparison between great offenses. But defenses have a lower bound, and back when shutouts were routine, it's mostly a matter of whose schedule happened to be a bit harder.
As for the possession argument, that's an entirely different factor. Using score data only, we'd have to make inferences. Possession data would be a good solution to differentiate between defenses that yield only a handful of points per season.
Posted by: SportsRatings | January 11, 2012 at 08:48 PM