Stat Analysis

Advanced analytics on player and team performance

Success of Players by College Conference: Defense

by Tom Gower

In the Tennessee chapter of Football Outsiders Almanac 2017 (which is still available, along with this year's version), we examined whether the Titans' selections of pass-catchers from three schools outside the power conferences early in that year's draft posed particular risks. More broadly, we explored whether particular collegiate conferences were better at producing players, and particularly very good players, at specific positions on offense. In this piece, we expand that effort to the defensive side of the ball.

The methodology is the same we used in that Tennessee chapter. Our base measure of value is Pro Football Reference's Approximate Value (AV). Any Titans fan who has looked at the 2015 team page and compared Jeremiah Poutasi with 4 AV to Derrick Morgan's 3 is aware of the deep limitations of AV as a method of player evaluation. Nonetheless, AV is a comprehensive number that includes an adjustment for team unit quality, acknowledges player participation data, and uses league-wide honors to reward players with superior performance. Its limitations are more pronounced when comparing specific players, but to analyze players in the aggregate, it's a very useful tool.

Defining the power conferences is pretty easy. Schools that had a privileged path to a BCS title game are power conference schools. This includes teams from the ACC, the Big 12, the Big Ten, the Pac-12, the SEC, the old Big East (2007-2012), and Notre Dame. The schools that did not are "mid-majors," those FBS schools now commonly known as the Group of 5, and include the old Big East schools now playing in the American Athletic Conference; schools in FCS (formerly known as Division I-AA); and small schools that do not play Division I football.

We started our study with every defensive player in the last ten seasons, 2008 to 2017. First, we specifically split out all player-seasons with at least 3 AV, a rough estimate of "replacement-level" value on defense. This sample includes almost every player who played a significant rotational role over the past ten years. Then we split out a second sample that included seasons with at least 8 AV, essentially the star players who truly mattered. The 2017 Titans had five players with at least 8 AV, including three on defense (Kevin Byard, Jurrell Casey, and Wesley Woodyard).

Table 1 shows the first cut, players with at least 3 AV. A couple of things stand out in the table (aside from just how unsurprising the death of Big East football was). One is that the SEC produces an awful lot of defensive players, and especially an awful lot of defensive backs. On offense, other conferences produced more quarterbacks and tight ends, and only in producing wide receivers was the SEC well ahead of the pack. Here, they lead all Power 5 conferences at each position group, and it is not very close in three of the five positions. Elsewhere, the Big 12 is much better at producing defensive linemen than it is edge rushers, and the Pac-12 does not produce many cornerbacks but is better at putting safeties into the league.

Table 1. Player-Seasons with at Least 3 AV by College Conference, 2007-2016
Conference
DL Edge LB CB Saf Total
ACC/Notre Dame 119 154 168 110 103 654
Big 12 138 75 68 85 62 428
Big East 42 51 58 67 49 267
Big Ten 133 131 140 79 90 573
Pac-10/Pac-12 117 79 119 68 94 477
SEC 211 171 180 167 145 874
All BCS/Power 5 760 661 733 576 543 3273

Mid-Major 131 122 127 153 131 664
FCS 48 52 40 69 69 278
Small School 26 19 36 63 28 172
All Non-BCS/Power 5 205 193 203 285 228 1114

Total 965 854 936 861 771 4387

Table 2 looks at the next cut, players with at least 8 AV. The dominance of the SEC is not nearly as pronounced here. Perhaps highlighted by when Ndamukong Suh of Nebraska and Gerald McCoy of Oklahoma were the second and third selections in the same draft, the Big 12 has produced plenty of very good defensive linemen. The ACC is tops at producing edge rushers, and schools from the Big Ten may no longer deserve the scorn they earned from first-round busts like Erasmus James. But if you take a Big Ten safety, don't expect him to have (m)any great seasons.

Table 2. Player-Seasons with at Least 8 AV by College Conference, 2007-2016
Conference
DL Edge LB CB Saf Total
ACC/Notre Dame 30 49 52 10 16 157
Big 12 45 27 18 13 11 114
Big East 13 24 11 13 11 72
Big Ten 32 47 49 16 9 153
Pac-10/Pac-12 26 26 34 16 14 116
SEC 52 45 56 25 23 201
All BCS/Power 5 198 218 220 93 84 813

Mid-Major 31 34 32 14 17 128
FCS 4 9 10 13 6 42
Small School 6 3 11 10 3 33
All Non-BCS/Power 5 41 46 53 37 26 203

Total 239 264 273 130 110 1016

Absolute numbers may not be the most interesting part of this. Instead, looking only at players who earn NFL roles, what is the chance he has a very good season?

Table 3. Percentage of 3+ AV Player-Seasons with
at Least 8 AV by College Conference, 2007-2016
Conference
DL Edge LB CB Saf Total
ACC/Notre Dame 25.2% 31.8% 31.0% 9.1% 15.5% 24.0%
Big 12 32.6% 36.0% 26.5% 15.3% 17.7% 26.6%
Big East 31.0% 47.1% 19.0% 19.4% 22.4% 27.0%
Big Ten 24.1% 35.9% 35.0% 20.3% 10.0% 26.7%
Pac-10/Pac-12 22.2% 32.9% 28.6% 23.5% 14.9% 24.3%
SEC 24.6% 26.3% 31.1% 15.0% 15.9% 23.0%
All BCS/Power 5 26.1% 33.0% 30.0% 16.1% 15.5% 24.8%

Mid-Major 23.7% 27.9% 25.2% 9.2% 13.0% 19.3%
FCS 8.3% 17.3% 25.0% 18.8% 8.7% 15.1%
Small School 23.1% 15.8% 30.6% 15.9% 10.7% 19.2%
All Non-BCS/Power 5 20.0% 23.8% 26.1% 13.0% 11.4% 18.2%

Total 24.8% 30.9% 29.2% 15.1% 14.3% 23.2%

Table 3 helps clarify some of the results from Table 2. The SEC produces plenty of players, but they were no more likely than players from other conferences to be particularly good. In particular, their edge rushers stand out the way Big 12 quarterbacks did on offense: likely to get a shot but overall not as good a bet as players from a different conference. Pac-12 cornerbacks may not be numerous, but they are pretty good bets, while ACC corners are not. Smaller schools, mid-majors and below, produce plenty of players, but by and large, they are not good bets to become standout defenders. (If you don't have FOA 2017 handy for comparison, similar analysis on offense showed higher success rates for offensive players from these types of schools.)

Like tight ends on offense, corners and safeties stand out because of the relative paucity of 8-plus-AV seasons. Over twice as many players in each front seven position group make it to that threshold as defensive backs, even though the overall number of players is not that different.

What does this mean for particular prospects? Maybe something, or maybe nothing. Looking at first-round picks by conference and position would be a different exercise, but the lesson might be the one we had for the Titans after they took Corey Davis from a mid-major school in the first round last year: there are no good comparables. Prospects succeed or fail on their own merits. One of my big lessons from writing eight years of draft retrospectives is that even great prospects from great schools will sometimes fail. There is no flawless prospect, and this study suggests additional caution may be in order before declaring that your ACC corner, SEC edge rusher, or FCS defensive lineman is destined for stardom.

Comments

3 comments, Last at 24 Jul 2018, 11:30pm

1 Re: Success of Players by College Conference: Defense

by Aaron Brooks Good Twin // Jul 24, 2018 - 3:39pm

Questions:

How was Utah handled? Were all their seasons included in Pac-10/12, or only their post-inclusion years? Similarly Rutgers? Are they a Big Ten team, or only since 2013?

How are guys who transferred/grad transferred counted? Is Russell Wilson an ACC player, a Big Ten player, or both?

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2 Re: Success of Players by College Conference: Defense

by LionInAZ // Jul 24, 2018 - 5:49pm

Nebraska and Maryland also.

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3 Re: Success of Players by College Conference: Defense

by Tom Gower // Jul 24, 2018 - 11:30pm

Conference and school where the player last played in college. Russell Wilson was counted as a Big Ten player. Von Miller (Texas A&M, 2011 draft) was a Big 12 player. Johnny Manziel (Texas A&M, 2014 draft) was an SEC player.

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