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.

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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 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.

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 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.)

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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.