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20 Sep 2012

Varsity Numbers: A Disruptive Presence

by Bill Connelly

Last Saturday morning, I published a preview of the Michigan State-Notre Dame game at SB Nation. In it, I found a really interesting tidbit to share that hinted at the Michigan State secondary's general level of aggressiveness.

It will be interesting to see how much success the Irish see in this regard against an incredibly aggressive Michigan State secondary. Through two games, State opponents have thrown 38 incompletions -- nearly half of those (17) were incomplete because they were either intercepted or broken up by a State defender.

As soon as I found that, I realized what my next Varsity Numbers column would be about. As I have gone about writing previews of every college team these past two offseasons, I have become as interested in stats that track personality as much as quality. It's one thing to say a team ranks 10th in Passing S&P+. It's another to piece together how they get there. Each team has it's own composite of sack rates (standard downs and passing downs), opponents' run-pass ratios, and, of course the number of passes they intercept or break up. Call it passes defensed or passes defended, but looking at the percentage of passes a defense can get its hands on both hints at general quality and an overall level of aggressiveness that we might not otherwise know.

Naturally, then, I threw together a comparison of a team's passes defensed and the number of incompletions its opponents have thrown. I took it another step, though, and added in a look at another common box score stat, the tackle for loss.

So below you'll find all of college football's 124 teams ranked by what I'm calling Disruption Rate. Disruption Rate is a team's passes defensed and tackles for loss divided by its total plays. You'll also find "PD%," which is a team's ratio of passes defensed to incomplete passes, and "TFL%," which is a team's ratio of tackles for loss to total plays. You could also look at the ratio of TFLs to plays that were not incomplete passes (since a play cannot result in both an incomplete pass and a tackle for loss … though Georgia's Jarvis Jones might pull it off at some point anyway). That might be a better way to go about that, but we'll keep it simple for now. For comparison, we will also include each team's current rankings in both raw Defensive S&P and the opponent-adjusted Defensive S&P+, which is still somewhat affected by preseason projections.

Now, the correlations between disruption and quality are there, just as you think they would be. The correlation between disruption and Defensive S&P is a very high 0.69; between tackles for loss and Defensive S&P, it is 0.47. But there are some fun outliers we will look at after the enormous table below.

Disruption Rate

Defense PD% Rk TFL% Rk Disruption
Rate
Rk Def. S&P
Rk
Def. S&P+
Rk
Connecticut 44.2% 14 17.6% 1 28.0% 1 7 10
Florida State 37.0% 38 16.0% 3 26.5% 2 2 5
Hawaii 33.3% 60 16.1% 2 23.2% 3 82 87
LSU 46.7% 9 11.2% 24 23.0% 4 4 3
BYU 45.9% 10 13.9% 7 22.7% 5 6 6
South Alabama 40.5% 22 14.7% 5 22.6% 6 30 67
Rutgers 39.5% 26 13.4% 8 22.6% 7 8 9
Stanford 41.5% 18 12.0% 15 22.1% 8 17 8
Alabama 43.9% 15 11.9% 18 22.0% 9 1 1
Arizona State 43.2% 16 13.0% 10 21.5% 10 15 26
TCU 48.3% 4 8.9% 52 21.4% 11 21 30
Oregon State 38.9% 30 9.8% 36 21.3% 12 11 11
Western Michigan 47.4% 7 12.1% 13 21.2% 13 53 72
UCLA 41.4% 19 10.3% 33 21.0% 14 39 36
Missouri 40.5% 22 13.4% 9 20.8% 15 36 16
Purdue 45.5% 11 10.3% 34 20.5% 16 22 41
Tulsa 30.6% 80 14.9% 4 20.0% 17 56 94
N.C. State 28.9% 87 14.2% 6 19.8% 18 44 50
South Carolina 36.4% 43 12.0% 16 19.6% 19 16 14
San Jose State 36.8% 39 11.9% 17 19.2% 20 66 104
Defense PD% Rk TFL% Rk Disruption
Rate
Rk Def. S&P
Rk
Def. S&P+
Rk
Cincinnati 32.3% 69 12.1% 14 19.1% 21 14 25
Ohio 41.1% 20 7.9% 72 18.7% 22 57 61
Michigan State 35.7% 49 7.7% 74 18.7% 23 13 7
Iowa State 38.6% 32 8.1% 68 18.6% 24 18 17
Minnesota 39.3% 27 8.6% 62 18.5% 25 29 44
Western Kentucky 36.8% 39 10.6% 28 18.4% 26 54 74
Ohio State 53.1% 1 6.5% 98 18.4% 27 63 51
North Carolina 36.4% 43 12.6% 11 18.2% 28 111 92
Oklahoma State 30.6% 79 11.6% 22 18.2% 29 62 62
Vanderbilt 36.4% 43 11.9% 19 18.0% 30 38 31
Oregon 51.2% 2 8.8% 57 18.0% 31 3 2
Utah 35.6% 50 9.7% 38 17.9% 32 23 20
Oklahoma 33.3% 60 9.3% 43 17.8% 33 5 4
San Diego State 33.3% 60 11.7% 21 17.8% 34 59 78
Utah State 39.6% 25 8.0% 70 17.5% 35 12 19
Wisconsin 45.1% 13 6.0% 106 17.4% 36 28 23
West Virginia 35.5% 51 11.0% 26 17.3% 37 20 29
Texas 37.1% 36 10.3% 32 17.3% 38 27 18
Syracuse 28.1% 95 12.6% 12 17.3% 39 85 84
Georgia 42.9% 17 9.0% 47 17.2% 40 32 28
Defense PD% Rk TFL% Rk Disruption
Rate
Rk Def. S&P
Rk
Def. S&P+
Rk
Illinois 40.5% 22 8.8% 55 17.1% 41 60 39
Georgia Tech 31.4% 77 9.0% 48 17.1% 42 25 37
Fresno State 38.2% 33 11.0% 25 17.0% 43 71 100
USC 35.4% 52 9.3% 45 16.7% 44 47 32
Washington State 33.9% 59 9.0% 50 16.7% 45 76 98
Arizona 37.1% 37 7.1% 90 16.7% 46 40 33
Texas A&M 24.1% 112 11.5% 23 16.5% 47 33 24
Maryland 26.7% 98 11.8% 20 16.3% 48 10 15
Notre Dame 32.6% 65 8.6% 60 16.2% 49 19 12
Temple 39.1% 28 9.5% 42 16.1% 50 37 64
Texas Tech 32.4% 68 8.9% 53 15.9% 51 9 13
Kansas State 28.6% 88 10.9% 27 15.8% 52 58 80
UNLV 36.4% 43 6.2% 104 15.8% 53 69 90
Indiana 34.9% 54 9.0% 51 15.7% 54 83 106
Florida International 34.7% 56 8.0% 69 15.6% 55 95 71
UTEP 36.7% 41 7.6% 75 15.6% 55 88 73
Iowa 31.4% 76 9.7% 39 15.6% 57 26 22
Florida 30.4% 83 7.7% 73 15.5% 58 43 27
Baylor 33.3% 60 6.9% 92 15.4% 59 31 49
Northern Illinois 45.2% 12 9.5% 40 15.4% 60 55 69
Defense PD% Rk TFL% Rk Disruption
Rate
Rk Def. S&P
Rk
Def. S&P+
Rk
Ole Miss 48.0% 5 9.8% 37 15.3% 61 108 107
Pittsburgh 34.1% 58 7.5% 77 15.1% 62 89 79
Nebraska 29.5% 85 9.2% 46 14.8% 63 65 59
Idaho 32.4% 67 8.6% 60 14.7% 64 79 91
Clemson 32.5% 66 8.0% 71 14.4% 65 42 52
California 25.7% 101 10.4% 31 14.3% 66 84 46
Kansas 37.5% 34 7.4% 81 14.3% 66 52 54
Houston 25.6% 102 10.4% 30 14.1% 68 110 53
Wake Forest 26.7% 98 8.8% 57 14.0% 69 74 66
Central Michigan 47.4% 7 7.2% 86 13.8% 70 99 122
Colorado 32.1% 71 9.3% 44 13.7% 71 107 96
Duke 30.4% 82 7.3% 85 13.6% 72 96 110
UTSA 32.0% 72 6.3% 101 13.5% 73 64 115
Virginia Tech 25.0% 105 10.2% 35 13.4% 74 35 21
SMU 32.2% 70 5.9% 109 13.4% 75 92 57
Louisville 34.9% 54 5.3% 116 13.4% 76 24 34
Kent State 31.6% 74 8.9% 54 13.3% 77 102 102
Central Florida 24.4% 110 8.2% 66 13.2% 78 50 42
Northwestern 24.6% 109 7.0% 91 13.2% 79 51 58
Buffalo 23.5% 113 10.4% 29 13.2% 80 113 120
Defense PD% Rk TFL% Rk Disruption
Rate
Rk Def. S&P
Rk
Def. S&P+
Rk
North Texas 25.0% 105 8.2% 65 13.2% 81 90 93
Air Force 36.4% 43 7.3% 84 13.1% 82 105 105
Mississippi State 35.0% 53 6.3% 102 13.0% 83 41 48
East Carolina 19.2% 120 8.5% 63 12.9% 84 49 56
UL-Lafayette 25.5% 103 8.3% 64 12.9% 85 81 75
Miami (Ohio) 30.6% 80 8.2% 67 12.9% 86 118 111
Akron 20.6% 117 9.5% 41 12.9% 87 77 112
Bowling Green 29.2% 86 9.0% 49 12.7% 88 91 83
Texas State 31.6% 74 3.7% 122 12.7% 89 109 118
Rice 48.0% 5 6.8% 93 12.7% 90 120 114
UL-Monroe 38.7% 31 3.1% 124 12.6% 91 106 101
Nevada 28.6% 88 4.8% 118 12.6% 92 78 86
South Florida 25.0% 105 8.8% 56 12.6% 93 46 47
Tennessee 22.0% 116 7.6% 76 12.4% 94 67 63
Washington 28.1% 95 7.4% 79 12.2% 95 72 43
Toledo 28.2% 93 7.2% 87 12.2% 96 98 77
Ball State 31.3% 78 5.9% 110 12.2% 97 103 109
Army 50.0% 3 5.2% 117 12.1% 98 123 123
Arkansas 25.5% 104 6.8% 94 12.0% 99 73 68
UAB 28.6% 88 7.2% 88 12.0% 100 101 97
Defense PD% Rk TFL% Rk Disruption
Rate
Rk Def. S&P
Rk
Def. S&P+
Rk
Louisiana Tech 34.2% 57 5.4% 115 11.8% 101 61 82
Auburn 33.3% 60 6.2% 103 11.6% 102 93 40
Boston College 40.8% 21 3.6% 123 11.5% 103 48 45
Miami 29.7% 84 6.8% 95 11.5% 104 80 60
Troy 28.2% 93 6.0% 106 11.4% 105 75 95
Michigan 17.6% 121 8.7% 59 11.4% 106 86 65
Marshall 26.8% 97 6.4% 99 11.0% 107 104 85
Southern Miss 22.7% 115 7.2% 89 10.8% 108 115 70
Penn State 24.2% 111 7.3% 82 10.8% 109 45 35
Florida Atlantic 39.1% 28 5.9% 110 10.7% 110 117 113
Kentucky 36.0% 48 6.7% 96 10.7% 111 97 81
Tulane 25.0% 105 6.3% 100 10.6% 112 116 99
New Mexico State 19.4% 119 7.3% 83 10.5% 113 114 119
Virginia 28.3% 92 4.3% 121 10.4% 114 68 55
Wyoming 36.7% 42 5.8% 112 10.4% 115 94 88
New Mexico 28.6% 88 5.6% 114 10.2% 116 121 124
Colorado State 23.1% 114 6.1% 105 10.1% 117 70 76
Boise State 26.1% 100 5.7% 113 9.9% 118 34 38
Arkansas State 31.8% 73 6.7% 96 9.8% 119 119 103
Massachusetts 37.5% 34 4.4% 119 9.7% 120 122 117
Defense PD% Rk TFL% Rk Disruption
Rate
Rk Def. S&P
Rk
Def. S&P+
Rk
Middle Tennessee 16.0% 122 7.5% 78 9.5% 121 87 116
Eastern Michigan 14.3% 123 7.4% 80 9.4% 122 112 89
Navy 20.0% 118 5.9% 108 8.5% 123 124 121
Memphis 10.4% 124 4.4% 120 6.4% 124 100 108

Alabama is both disruptive and fantastic. Of course they are. So are LSU, Rutgers, et cetera. But there are some interesting contradictions among some teams.

Disruptive But Bad: Hawaii, North Carolina, Ole Mis, San Jose State, Syracuse, Houston. All of these teams rank at least 40 spots higher in disruption than they do in Defensive S&P. Hawaii is perhaps the most impressive of the bunch. Almost one full quarter of the Warriors' defensive plays result in either a pick, a break up, or a tackle for loss. The other three-quarters, meanwhile, are probably going for a big gain. Part of this has to do with the contradiction on their schedule so far -- they got torched by USC, then blew up poor Lamar -- but they did still log six tackles for loss against the Trojans, too. North Carolina similarly torched Elon, but they also recorded 16 tackles for loss in losses to Louisville and Wake Forest. They are aggressive and fast, but the breakdowns are frequent.

Passive But Solid: Penn State, Boise State, Boston College, Louisville. All four of these teams rank in the top 50 in Defensive S&P and at least 50 spots lower in disruption. Boise State held Michigan State to a reasonably decent 5.1 yards per play and limited Miami (Ohio) to 4.4, but the tackles for loss have been minimal, and they have defensed just six passes (three picks, three passes broken up) in two games. Penn State, meanwhile, has defensed just eight in three games, but solid front seven play has still pushed them to 45th in Defensive S&P.

INTs and Luck

One thing I played with at Football Study Hall this past offseason was the relationship of interceptions to passes broken up. On average in 2012, interceptions make up about 20 percent of all passes defensed. And while defensing passes is something that can be replicated from year to year, the number of footballs you actually reel in sometimes cannot. If your percentage of interceptions (as related to total passes defensed) creeps into the mid-30s or 40s, your turnover margin is probably going to be artificially high and will regress back toward 20 percent at some point. You may have a single player with particularly good hands, but you're still probably getting a bit lucky if that percentage is high.

With that in mind, let's take a quick look at teams' interception percentages.

Likely To Fall Soon (or, you know, next year): Virginia Tech (7 PDs, 4 INTs), North Texas (9 PDs, 5 INTs), UTSA (8 PDs, 4 INTs), Mississippi State (14 PDs, 7 INTs), Boise State (6 PDs, 3 INTs), Texas (13 PDs, 6 INTs). Virginia Tech has made the most of its limited pass defensing opportunities, but if they don't begin to break on MORE passes, that might not make a difference. Of course, last week's loss to Pittsburgh exposed some potential potential issues against the run that could bite the Hokies a lot harder than interceptions luck.

Likely To Force More Turnovers Soon(ish): Wisconsin (23 PDs, 0 INTs), Nevada (18 PDs, 0 INTs), Ball State (15 PDs, 0 INTs), Virginia (13 PDs, 0 INTs), Louisiana Tech (13 PDs, 0 INTs). If Wisconsin had picked off the national average of 20 percent of their passes defensed, they'd have forced an extra four-to-five turnovers so far in just three games. Do you think that may have made a difference in their three-point loss to Oregon State or their tighter-than-expected wins over Northern Iowa and Utah State? The Badgers' offense is obviously not where it should be, but some stone hands and bad luck in the secondary have been detrimental to the Wisconsin cause as well.

Week 4 F/+

Your Week 4 F/+ rankings are live. As is always the case with early-season FO rankings, there have been some impressive week-to-week shifts thus far.

2012 F/+ Rankings (After 3 Weeks)
F/+ Rk Team Record F/+ Last Week Change S&P+ Rk FEI Rk
1 Alabama 3-0 +59.4% 1 0 383.4 1 0.324 1
2 Oregon 3-0 +37.3% 3 1 312.0 2 0.231 8
3 Florida State 3-0 +35.9% 6 3 297.2 3 0.275 3
4 LSU 3-0 +32.2% 2 -2 285.5 4 0.259 5
5 Oklahoma 2-0 +29.0% 4 -1 266.0 6 0.291 2
6 West Virginia 2-0 +26.8% 11 5 266.1 5 0.245 7
7 Texas 3-0 +21.8% 9 2 250.6 7 0.221 9
8 Notre Dame 3-0 +21.2% 8 0 240.9 14 0.257 6
9 Georgia 3-0 +20.6% 7 -2 246.3 9 0.219 11
10 Texas Tech 3-0 +20.5% 22 12 246.2 10 0.217 12
11 Stanford 3-0 +19.6% 13 2 241.8 13 0.220 10
12 TCU 2-0 +18.8% 5 -7 240.5 15 0.211 14
13 Florida 3-0 +18.4% 15 2 227.6 21 0.266 4
14 Oklahoma State 2-1 +16.7% 16 2 244.7 11 0.148 25
15 BYU 2-1 +16.4% 26 11 246.3 8 0.133 30
F/+ Rk Team Record F/+ Last Week Change S&P+ Rk FEI Rk
16 USC 2-1 +16.3% 10 -6 230.2 19 0.210 15
17 South Carolina 3-0 +15.3% 20 3 227.8 20 0.203 17
18 Michigan State 2-1 +15.1% 18 0 232.1 17 0.178 21
19 Ohio State 3-0 +13.6% 12 -7 224.3 25 0.186 20
20 Georgia Tech 2-1 +13.6% 27 7 223.3 26 0.190 19
21 Cincinnati 2-0 +13.3% 32 11 218.3 32 0.210 15
22 Clemson 3-0 +13.3% 24 2 221.9 27 0.192 18
23 Arizona State 2-1 +12.7% 40 17 233.0 16 0.124 31
24 Michigan 2-1 +12.2% 17 -7 242.6 12 0.067 49
25 Nebraska 2-1 +12.1% 25 0 226.6 22 0.144 26

"What The..." Team of the Week: Texas Tech. I know the Red Raiders haven't played anybody yet. Obviously. But it's one thing to beat bad teams easily. It's another to do what they've been doing. They have beaten Northwestern State, Texas State, and New Mexico by a combined 151 to 30. They outgained those three teams, 1,793 yards to 481. And from what I can tell, head coach Tommy Tuberville hasn't exactly left his starters in for an inordinate amount of time. With their experience level, Tech received a rather favorable projection from us in the Football Outsiders Almanac 2012, but they have already improved on that projection significantly, ranking in the top 12 in both S&P+ and FEI. Up next: a really interesting trip to Ames to face an Iowa State team that has also exceeded expectations thus far.

This Week At SB Nation

I've had a bit of a slower week than normal at SBN, preparing for the greatest, dumbest road trip I've ever taken.

Posted by: Bill Connelly on 20 Sep 2012

2 comments, Last at 21 Sep 2012, 1:56am by Kal

Comments

1
by Aaron Brooks Go... :: Thu, 09/20/2012 - 6:19pm

Disruptive But Bad -- We call this the DeAngelo Hall Memorial Division

Passive But Solid -- The Tony Dungy

2
by Kal :: Fri, 09/21/2012 - 1:56am

I would have expected Oregon to rank higher on the TFL number; one of the things I think I've seen is a lot of sacks and stops of runners. But that appears to be something of an illusion. What's interesting is the very high passes defensed number; over half of the passes have been defensed. That's gotta be a relic of the three games we've played and not particularly indicative.

Have you thought about running this against last year to see what it looks like?