College Football Conference Comparison Part 3: Defense

In Part 2 of my multi-part series College Football Conference Comparison, I looked at penalties. Part 3 will focus on defenses.

All graphics in this post are looking at data since the 2000-2001 season and include the teams in the conferences at that time. So for example, Colorado is included in the Big 12’s rankings until 2010, from there it is included in the Pac 12’s rankings.

The first three graphics are all looking at the same data points, but just shown a different way. The first two show average passing yards allowed by the defenses as well as average rushing yards allowed by the defenses. The third graphic has the two data points above, but has an additional bar which represents the difference between the passing and rushing yards allowed.

Passing Yards Allowed:

The SEC took the top spot only allowing 207.31 yards passing on average. The independent schools closely followed allowing 207.40 yards per game. The Pac 12 was the worst of the power five conferences and 12th overall allowing 237.52 passing yards per game.

While leading on average, an SEC team has not allowed the fewest passing yards per game since the 2015-2016 Georgia Bulldogs. In fact only three times has the SEC actually had a team that led this statistic – Georgia did once, Alabama twice.

Rushing Yards Allowed:

Again, the above graphic is the same as the first, just sorted in terms of fewest rushing yards allowed.

The Big East (which is no longer around) took the top spot, followed by the SEC and Pac 12. Spots 2-6 are all filled by the power five conferences for fewest rushing yards allowed per game. Only 4 times over the last 19 seasons has a non-power five conference school led this statistic. TCU did it twice when they were not in the Big 12, so really only 2 current non-power five schools have led this since the 2000-2001 season.

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The next graphic looks at the difference between a conference’s average passing yards allowed and rushing yards allowed.

Passing and Rushing Yards Difference:

Independent schools led the way with 49.4 yards difference in their pass and rush yards allowed. The first power five conference is the SEC in 5th place and the Big 12 and Pac 12 take the 12th and 13th spots with 80.5 and 91.7 yards allowed difference, respectively.

This graphic does contradict the others just a bit. As you can see the top 4 conferences above (Independent, MWC, Sun Belt, MAC) all rank 8, 10, 12, and 11 is rushing yards allowed, so because of this they will rank better by this difference measure. I think it is important to include the difference because it give us an idea of how balanced a defense is. Including the passing and rushing yards allowed measures too ensures we are not artificially ranking a conference too high or too low.

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The final two graphics are looking at the number of points defenses allowed per game. The first shows the average per season per conference as well as a table showing the individual seasons by conference.

The second graphic plots the average points allowed per team per season to show the trend over time. The points are colored by the number of plays the defense allowed. This only included power five conferences as well as independent schools.

Points Allowed:

The SEC takes first again in the number of points allowed. With how well they ranked in both passing and rushing yards allowed (1st and 2nd) this is not too shocking. We also see the SEC’s average points allowed has not increased as much as some others since the 2000-2001 season.

The Big 12 was the worst among power five conferences allowing 26.5 points a game. In recent seasons the Big 12 has been known for poor defense and very high scoring games. When looking back at previous seasons, the Big 12 has increased the number of points allowed more than any other team by far.

Summary:

Passing Yards Allowed: SEC
Rushing Yards Allowed: Big East
Passing and Rushing Yards Difference: Independent
Points Allowed: SEC

Updated Average Ranking:
1) SEC
2) Big Ten
3) Independent

Intro
Part 1
Part 2
Data: https://www.sports-reference.com/cfb/