Brian Nemhauser·
Advanced StatsDefense
··7 min read

Battle of the Best: 2013 Seahawks Defense vs 2015 Broncos Defense

There has been an abundance of talk that this 2015 Denver Broncos defense is among the best in league history. They have been fantastic. Good enough, in fact, to be worth putting through the gauntlet to see how they stack up with a historically great defense that played in the Super Bowl just two years ago. One-by-one, I have examined the 2013 Seahawks versus titans of years gone. Apples-to-apples comparisons across generations and rule changes are difficult, but the method used here aims to do exactly that. It is not clear which defense will come out on top as we begin. The goal is to be objective and to enjoy the battle.

Previous Articles In Series:

Ground Rules:

  • No player comparisons: Generalities about players are irrelevant because they are just opinion. Number of Pro Bowlers or Hall of Famers often reflects popular opinion more that actual talent. Should someone want to quantify the quality of each player at each position and aggregate the total talent, I would love to read it. Until then, we will look at the whole team performance.

 

  • Relative > Absolute: A team that holds opponents to 11.4 points per game (ppg) sounds better than a team that holds opponents to 14.2 ppg. But when the average offense scored 15 ppg in the year of the first team and the average offense scored 27 ppg in the year of the second team, the judgment should shift. We will heavily slant toward how the team performed in the era/year in which they played. This will also help to account for rule changes.

 

  • Quality of opponent matters: A team that has the best opponent scoring average in the league, and does it during a year when scoring is way up sounds dominant. But what if they played in the 2005 NFC West? Who you play, and how you perform against those opponents needs to be taken into account.

 

  • Strength of offense: A defense that has to make up for a horrible offense gets extra credit. We will compare the offenses these defenses played with at a high level.

 

  • Championships: It should not be the ultimate arbiter, but it does have to be factored in. A defense that ends the year as a champion deserves credit for the ultimate accomplishment, and one that fails in that game deserves additional scrutiny.

 

  • Analysis versus facts: I will give my opinion at the end of each article about which defense was superior and why. You may come to a different conclusion. The facts should not be disputable. My interpretation of them is open to debate.

Why the 2015 Broncos

The Broncos were the first team other than the Seahawks to lead the NFL in yards allowed since 2011. Their star power is indisputable at every level. DeMarcus Ware and Von Miller are hellhounds on the outside. Malik Jackson, Shane Ray, Derek Wolfe and others add to pass rush arsenal few can match. Aqib Talib, T.J. Ward, Chris Harris Jr., and company make up one of the best secondaries in the game. They beat the Patriots twice, including a dominating performance in the AFC Championship.
All accomplishments are relative. That will be factored into the battle below. Scoring is down almost a point per game since 2013. Let’s see if other league trends impact the degree to which Denver’s defense should be considered special.

Round 1: Yards Allowed

Team League Avg Yards/Game Opponent Yards/Game Std Dev League Rank
2015 Broncos 352.7 283.1 -2.25 1
2013 Seahawks 348.5 273.6 -2.40 1

The Seahawks allowed nearly 10 fewer yards per game than the Broncos, and both teams finished atop the rankings, but the Seahawks take the lead in this category due to a better performance relative to what other league defenses were doing that year. Keep in mind, standard deviation looks at the spread of results across the league. It was 31.2 in 2013 for yards per game and 30.9 this year. That means that despite a greater spread of results in 2013, the Seahawks defense still stood out more than Denver’s in this category.

Team League Avg Yards/Play Opponent Yards/Play Std Dev
2015 Broncos 5.5 4.4 -2.65
2013 Seahawks 5.34 4.4 -2.22

Some teams give up more yards per game simply because their offense leaves them on the field a lot. Looking at yards per play allows us to see an even better apples-to-apples look at two defenses. The Broncos have a dominant advantage in this category despite giving up the same yards per play as the 2013 Seahawks. This would indicate the Broncos are probably the more efficient defense in terms of surrendering yardage. This one is close but…

ROUND ONE WINNER: 2015 Broncos

 

Round 2: Points Allowed

Team League Avg Points/Game Opponent Points/Game Std Dev League Rank
2015 Broncos 22.8 18.5 -1.25 4
2013 Seahawks 23.4 14.4 -2.23 1
This round starts with a big right hook from Seattle. The Seahawks gave up four fewer points per game despite playing in a year when teams were scoring more points than what the Broncos faced. They ranked tops in the NFL in this category, where the Broncos were just fourth. It comes as no surprise that the standard deviation differences is massive.
Team League Avg Points/Play Opponent Points/Play Std Dev
2015 Broncos 0.354 0.287 -1.29
2013 Seahawks 0.360 0.233 -2.07

 

It gets a tiny bit closer when looking at efficiency per play, but not much. This one is clearcut.

ROUND TWO WINNER: 2013 Seahawks

Round 3: Schedule

Up to this point, we have been comparing the two defenses performance against league averages. But neither the Seahawks nor the Broncos played every opposing offense in the league. We need to get specific about which offenses they played, and how they did relative to the averages of those offenses.

Team Aggregate Opponents PPG Opponent PPG Std Dev
2015 Broncos 21.5 18.5 -1.0
2013 Seahawks 22.1 14.4 -2.5

The Broncos 16 regular season opponents scored an average of 21.5 points per game, just below the league average (22.9). Seattle faced opponents who averaged slightly below the league average (23.4) as well. The Seahawks held their opponents much farther below their season averages than the Broncos.

Let’s step away from the regular season for a moment though and just see how both teams did against the best offenses in the league that year. The best versus the best.

 

Team GMs VS TOP 10 OFF (incl playoffs) +/- Opp Avg
2015 Broncos 7* -3.7
2013 Seahawks 3 -19.9

Denver faced a bunch of top offenses. They did not do wonderfully against them. Their points allowed per game rose from their average of 18.5 to 23.1. The Seahawks dropped their average from 14.4 to 10.0 against the best offenses, including their dominant Super Bowl performance against the best offense in history. Denver will face one more Top 10 offense in the Super Bowl, which will impact these results, but not by much.It is also worth noting that one of the Top 10 offenses the Broncos faces was the Bengals without Andy Dalton, so it would be hard to consider that team near its best. They also faced the Steelers with an injured Ben Roethlisberger, and without Antonio Brown, Le’Veon Bell, or DeAngelo Williams.The Broncos faced more top-flight offenses, but their performance against them was underwhelming, whereas the Seahawks stepped up their game against the best.

ROUND THREE WINNER: 2013 Seahawks

Round 4: Takeaways

Team League Avg Takeaways/Game Takeaways/Game Std Dev League Rank
2015 Broncos 1.5 1.7 0.6 8
2013 Seahawks 1.6 2.4 2.3 1

The numbers flip here. The higher, the better. Seattle was significantly more adept at taking the ball away from their opponents than the Broncos. Denver was pretty close to a league average defense when it comes to creating turnovers. This round is not close.

ROUND FOUR WINNER: 2013 Seahawks

Round 5: Offenses

Let’s take a look at just how much help or harm the other side of the ball did to these defenses. Admittedly, I will not go is deep here or else this would turn into an equally long assessment of each offense. Instead, we will stick to some absolute numbers and get some relative information via league rankings.

Team OFF PPG OFF PPG Rank OFF YDS/GM OFF YDS/GM Rank TO/GM TO/GM Rank
2015 Broncos 22.2 19 355.5 16 1.94 29
2013 Seahawks 26.1 8 339 17 1.19 4

This one is interesting. The Broncos offense was clearly worse in terms of scoring, but was similar in yards. The stat that jumps out here is the turnovers. The Broncos offense turned the ball over at an alarming rate, ranking 29th in the NFL. This put considerably more strain on their defense than what the 2013 Seahawks offense did. This helps to explain at least some of the difference in points allowed.

ROUND FIVE WINNER: 2015 Broncos

Overall Winner: 2013 Seattle Seahawks

This is the only subjective part of the article. I look at these two defenses and see some similarities, but the Broncos biggest advantages were in yards per play and the fact that their offense put them in bad situations due to turnovers. Seattle dominated in points allowed, points per play, yards allowed, and turnovers forced, and by a pretty large margin in most.The 2015 Broncos are a great defense. They can help their legacy by finding some way to win this Super Bowl, but they will have to wait in line behind the 2013 Seahawks when awards are being given out for best defenses of all-time.

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