The Saints Defense (Not Run Game) is Why They’re Legit

The New Orleans Saints have been one of the most dominant teams in the NFL this year at 7-2, a big departure from last three seasons when the team finished 7-9 each year.

The Saints improved run game has been the talk of the town, with Twitter lighting up to label the Saints running success as a game-changer for the franchise.1

Then this morning I was listening to the Around the NFL Podcast and the first thing mentioned when discussing the Saints turnaround was their running game, while the defense was an afterthought.

This post focuses on the Saints, but it’s really an illustration of a larger points: 1) Running the football has a much smaller effect than most people think; and 2) Running doesn’t win games, you run because you’re winning. Drew Brees is on pace to throw 140 fewer passes this season, and it isn’t just because the team is running the ball better.

Let’s use the nflscrapR package to dig into exactly how much the Saints run game and defense are respectively impacting the team’s performance in terms of expected points added, a stat that is easily comparable between offense and defense. We’re also going to compare the 2017 Saints run game and defense from this season to their last three down years to get an idea of how much the team has improved in both areas.

Saints Run Game

Season Att Success Success Rate Points Added Per Att
2014 379 153 40.4 -0.03
2015 371 137 36.9 -0.05
2016 384 153 39.8 -0.03
2017 253 98 38.7 0.04

The Saints run game was losing points on average from 2014-2016, but it isn’t because they weren’t doing a poor job running the ball versus the rest of the NFL. Running the ball is generally a negative endeavor; The entire league is averaging -0.08 points added per attempt in 2017.

The numbers do show that the Saints run game has improved and is one of the best in the league in generating points. But one area to be concerned about is that the Saints success rate is lower than the average of the previous three seasons (39.0), meaning that most of the uptick in points added is due to long plays. Whether teams should prefer a steadily successful running game or one that breaks lots of long plays is an open question.

Saints Defense

Season Plays Success Success Rate Points Added Per Play
2014 1083 456 42.1 -0.14
2015 1075 471 43.8 -0.15
2016 1063 468 44 -0.12
2017 576 226 39.2 0.07

I’m framing the Saints defensive points added as a positive number if the defense is taking away expected points from its opponents, and a negative number if the reverse.

The Saints defense was one of the worst in the league the past few years, giving up an average of 0.14 more points per play than you’d expect. The Saints improved defense, especially against the pass, has the team in the top-10 this season in points added per play, versus dead last in 2014 and 2015, and fourth worst in 2016.

How Much More Valuable is the Saints Defense?

Play Type Points Added Per Play Vs Historical Plays Total Points Added Wins Added
Runs 0.08 253 19.4 0.6
Defense 0.21 576 119.0 3.8

Here’s a simple calculation using the difference in points added numbers on a per play basis versus prior years and multiplying by total plays.

The improvement in the Saints defense has been worth a little more than six times the run game this season, 119 points versus only 19.4. Using the estimate that each additional win equates to roughly 31 points in point differential, this translates into the Saints defensive improvement being responsible for 3.8 more wins so far this season, and the run game only worth 0.6 wins.

But is the Run Game Carrying the Offense?

Season Pass Att Success Success Rate Points Added Per Pass Att
2014 684 348 50.9 0.18
2015 700 337 48.1 0.20
2016 697 365 52.4 0.19
2017 307 153 49.8 0.27

Narratives are right that the Saints are relying more on the run game versus prior years with a 55 percent pass ratio this year versus an average of 65 percent the last three years. But it’s not because Drew Brees and the passing offense is paying less efficiently. The Saints are averaging 0.27 points added per pass play, the highest mark for the past four years. Some will argue that the run game is helping the pass game be more efficient with lower volume. But there isn’t much empirical evidence to suggest that lower volume leads to higher efficiency.

Conclusion

It’s not that the Saints haven’t been running the ball well. But before we draw conclusions watching games from what our eyes are telling us – Saints running more equals Saints winning more – we have to understand the fundamental concepts behind football value. One of those concepts is that the run game generally isn’t adding nearly as much value as passing. That’s why we should always look to other facets of a team’s improvement before blindly giving credit to the run game.

  1. I got into a little tiff with Geoff Schwartz about his misunderstanding of how running the ball affects performance.

Leave a Reply