Take a look at the Broncos pass defense this year, compared to the Broncos pass defense last year:
Three years ago, I looked at the Seattle pass defense and calculate how many standard deviations above average the Seahawks were. At the time, I compared them to an average of the other 31 defenses rather than an average of all 32 defenses, including themselves. I don’t know if there’s a right or wrong answer there, but I’m going to use the latter methodology today, which will explain why the numbers are slightly different.
Anyway, Seattle was 2.80 standard deviations above average in ANY/A allowed in 2013. That’s because Seattle’s pass defense allowed 3.19 ANY/A, while the league average was 5.89 ANY/A. That’s a difference of 2.70 ANY/A, and the standard deviation among the 32 pass defenses that year was 0.97. Divide 2.70 by 0.97, and you see that Seattle was 2.80 standard deviations above average.
The 2016 Broncos? They are allowing just 4.25 ANY/A. That is over a full yard “worse” than Seattle, but worse needs to be put in quotes. For starters, the league average is 6.25 ANY/A this year; in addition, the rest of the league is bunched together. The standard deviation for the 32 pass defenses is 0.74 ANY/A. That means the Broncos have a Z-Score of 2.69 standard deviations better than average (here, negative is better).
That puts Denver as the 5th best pass defense, by this metric, since 1970:
|Rk||Team||Year||ANY/A||Lg Avg||Lg StDv||Z-Score|
With two games left, there’s still a chance that the Broncos rise (or fall) in these rankings. But don’t let the 8-6 record fool you: Denver has a historically great pass defense. In fact, the 8-6 record might be the best evidence of that yet: that’s because Denver is bad at just about everything else. The Broncos are terrible at running and pretty bad at stopping the run; meanwhile, the passing offense is below-average, too. Given this team even an average pass defense, and they would likely be one of the worst teams in the league.