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Blogging about college football by an Oklahoma Sooners fan.

Nonstop Offense: Defensive Tempo

(This is the first in a series of articles analyzing the growing use of the no-huddle spread on college football.)

Previously, we tried to measure offensive tempo to determine how quickly teams ran offensive plays. While defenses have less direct effect on the pace of a game, it stands to reason that opponents’ offensive tempo can have an impact on a defense’s performance. However, as is the case with offenses, we seem to lack useful statistics to measure the pace at which defenses play—or, more aptly, the pace at which they are forced to play.
To gauge “defensive tempo,” Homerism derived a statistic based on the length of time per play for a defense. This reflects how quickly opposing offenses ran plays against a defense. To do so, Homerism subtracted teams’ total time of possession from the total minutes played for the season. For example, if a team played 12 games in 2008 (720 minutes) and had a total time of possession of 320 minutes, that team’s defense was on the field for 400 minutes on the year. Then, I divided that difference by the numbers of defensive plays in the season and adjusted that quotient to reflect average seconds per play.
Of the 120 FBS teams in college football, the average defensive tempo for 2008 is 26.773 seconds per play, with a median of 26.779. (Note that these numbers were calculated prior to the bowl season.) The top 10 in terms of quickest tempo:
Defensive Tempo (seconds/play)
1. Nevada (23.530)
2. UTEP (23.978)
3. Oklahoma State (24.017)
4. Marshall (24.057)
5. Rice (24.432)
6. Louisiana-Lafayette (24.767)
7. Arkansas State (24.781)
8. Idaho (24.896)
9. Buffalo (25.001)
10. Texas (25.048)
Given the prevalence of spread schemes and hurry-up offenses in the conference, the fact that two Big 12 teams can be found in this group makes sense. Additionally, half the conference ranks among the top 20.

The 10 slowest:

Defensive Tempo (seconds/play)
111. Army
112. South Florida
113. Virginia
114. Miami (Florida)
115. Virginia Tech
116. Kentucky
117. Tennessee
118. Syracuse
119. South Carolina
120. Rutgers
Three teams from the SEC in the bottom 10 seem consistent with the perception that the conference is heavy on run-oriented, ground-it-out offenses. Another three SEC teams can be found in the next group of 10.
Is there a relationship between defensive tempo and productivity? Somewhat.
For example, the correlation between defensive tempo and yards per play is -0.349. The negative sign indicates that as time per play declines—or tempo increases—yards allowed per play tend to increase. A slightly stronger correlation of -0.382 exists between tempo and points allowed per second.
It’s tough to draw solid conclusions from the relationships as evidenced here, as a number of factors could boost defensive tempo. For example, defenses that face pass-heavy offenses are likely to exhibit quicker defensive tempo.
However, a demonstrable relationship between defensive tempo and performance does appear likely. Consequently, it’s not unreasonable to cut quick defensive teams some slack for supposed underperformance. Conversely, some defensive prowess could be attributed to slower defensive tempo.

Next up, we'll take a look at ways to evaluate how a team's offensive tempo affects its defensive performance.
Below are the national defensive tempo rankings from quickest to slowest:
Defensive Tempo (seconds per play)
Nevada 23.530

UTEP 23.978
Oklahoma State 24.017
Marshall 24.057
Rice 24.432
Louisiana-Lafayette 24.767
Arkansas State 24.781
Idaho 24.896
Buffalo 25.001
Texas 25.048
Kansas 25.192
Colorado State 25.212
Kansas State 25.239
Nebraska 25.278
Louisiana-Monroe 25.496
Wisconsin 25.510
Purdue 25.575
Texas Tech 25.592
Oklahoma 25.684
Arkansas 25.717
Michigan State 25.717
Missouri 25.717
West Virginia 25.726
California 25.799
Baylor 25.823
Utah 25.943
Iowa State 25.952
Boise State 25.982
UAB 25.997
Ball State 26.036
Central Michigan 26.045
North Texas 26.048
Akron 26.071
Arizona 26.089
Temple 26.093
Iowa 26.105
BYU 26.159
Ohio 26.215
Notre Dame 26.281
Boston College 26.350
Penn State 26.353
Eastern Michigan 26.394
UNLV 26.415
Hawai'i 26.440
Texas A&M 26.455
Pittsburgh 26.456
Utah State 26.479
Stanford 26.495
North Carolina State 26.511
Air Force 26.560
SMU 26.562
New Mexico 26.564
Bowling Green 26.576
Georgia Tech 26.580
Western Kentucky 26.593
Houston 26.626
Arizona State 26.728
East Carolina 26.773
Fresno State 26.773
North Carolina 26.778
TCU 26.779
Colorado 26.819
Southern Mississippi 26.864
San Diego State 26.867
Northwestern 26.873
Minnesota 26.893
Louisville 26.907
Oregon 27.017
Kent State 27.033
Western Michigan 27.038
Washington 27.079
Ohio State 27.092
UCLA 27.109
Louisiana Tech 27.123
Indiana 27.163
Oregon State 27.211
Duke 27.232
Washington State 27.234
Middle Tennessee 27.251
Navy 27.281
Memphis 27.295
Florida Atlantic 27.327
Florida International 27.336
Cincinnati 27.358
Alabama 27.384
Tulsa 27.444
Connecticut 27.496
Mississippi 27.501
Wake Forest 27.523
New Mexico State 27.554
Toledo 27.567
Wyoming 27.612
Florida State 27.629
LSU 27.657
Troy 27.672
Georgia 27.676
Miami (Ohio) 27.771
Vanderbilt 27.783
Clemson 27.791
Illinois 27.817
San Jose State 27.823
Michigan 27.853
Auburn 28.022
Mississippi State 28.105
Northern Illinois 28.137
Tulane 28.186
Florida 28.216
UCF 28.289
Maryland 28.298
USC 28.328
Army 28.402
South Florida 28.459
Virginia 28.519
Miami (Florida) 28.707
Virginia Tech 29.029
Kentucky 29.156
Tennessee 29.171
Syracuse 29.178
South Carolina 29.210
Rutgers 29.376

Median 26.779
Average 26.773