Crunching The Numbers: Week 4

Welcome back to a new season of Crunching The Numbers! If you’re unfamiliar with what this is about, it is a home-brew stat-based method for ranking NFL teams. Think of it as BGN’s version of ESPN’s FPI, Football Outsider’s DVOA, or Five Thirty-Eight’s Elo. I wouldn’t ever suggest what I do is of the same caliber (it’s not), but it’s the same general idea. If you’d like to read more, an archive of every post on this topic can be found here.

I have added a new wrinkle to my formula this season - “derivative control.” Last season, I noticed that teams who were in the process of tanking (like the Eagles) had their scores artificially inflated by previous success early on in the season. I felt this was an inaccurate representation of their current performance, so I set out to change that.

If you look at the formula, it is divided into an offensive and defensive component. Each week I calculate each component individually and then add them together to get a final score. Starting in Week 5, I’ll be adding an extra step by subtracting the previous week’s score for each component from the current score (i.e. I’ll be subtracting Week 4’s score from Week 5). This difference will then be tacked onto Week 5’s offensive and defensive scores. If the difference is positive, it becomes a bonus. If the difference is negative, it becomes a penalty. Here is the offensive process visualized:

DIFF = OFF SCORE, WK5 - OFF SCORE, WK4

NEW WK5 OFF SCORE = OFF SCORE, WK5 + DIFF

The same process will be applied to the defense. What makes this interesting is that each week I will be subtracting the adjusted score from the current score to get the difference. If a team is consistently trending up or down this will create a positive feedback loop that can significantly affect their score later in the season to properly reflect their play. In this way, previous performance becomes less of a factor as the season moves on. (NOTE: For any engineers in the audience, I know this is not technically derivative control. But it’s a somewhat similar concept and I think the phrase sounds cool, so I’m using it. #DealWithIt)

Like last season, I’ll present the rankings, a discussion of why the Eagles are ranked where they are, a discussion of their next opponent, and some fun facts at the end. Now enough math, let’s get to the scores!

Crunching The Numbers Rank Index, Week 4

It should be noted that the following scores are index values, meaning they only have relative value. A score of 10 is only “good” if it is better than the other numbers in the set. There is not a scale of any kind to compare the scores against.

Why the Eagles are First(!)

Well look at that! Our very own Philadelphia Eagles grade out #1 overall in my formula. This is entirely caused by their insane point differential, which is the formula’s largest component. For their raw offensive score (3.82), they actually fall behind Oakland (5.82) and Dallas (4.04). And on defense (-0.31) they find themselves trailing teams like Baltimore (-0.05), Denver (-0.27), and Kansas City (-0.25).

While it’s nice to see them in first, it should be noted that the reason WHY is not exactly sustainable. They are not going to outscore every opponent 31-9 for the rest of the season. There will be a week (or two) when a team finds a way to score on the defense, and there will be a few more where Wentz has a bad game and the offense can’t get into a rhythm. And moreover, their status on top vastly increases the likelihood that they’ll trend down in my derivative control feature, which could make them fall faster as the season goes on.

With that being said, there is reason to believe the Eagles will remain in the top ten this season. The pass defense is lights out with only 6.2 YPA allowed and no touchdowns surrendered through the air. Their sack rate on offense is among the lowest in the league (3.8%) and they’re averaging 8 rushing first downs per game, which is second only to Dallas (11). These are sound fundamentals which can be sustained with good coaching (sans the zero passing touchdowns). As it stands now, the Eagles’ coaches are doing a hell of a job, so expect them to be competitive all season. Just don’t be surprised if they drop on the rankings as the season goes on.

Week 5 Reconnaissance: Detroit Lions

The Eagles head up to Michigan this week to take the 20th ranked Detroit Lions. That placing might seem generous for a 1-3 team, but all of their losses have been close and the offense has the ability to score. Regardless, if the Eagles can continue their high level of play, there is no excuse for not avenging last Thanksgiving’s embarrassment. The Lions have allowed a sack rate of 6.02% on offense and Stafford has been a modest turnover machine with an interception rate of 2.56%. Defensively, they’re only averaging 0.2 turnovers a game and allow an abysmal 47.1% of third down conversions. The Lions can prove to be a tough opponent at home, but the Eagles are simply the better team. If they lose it would be a huge disappointment off the bye and they would have nobody to blame other than themselves, especially since their matchup against the Redskins in Week 6 doesn’t really qualify this as a trap game.

Notes

The Broncos are in midseason form by only allowing an absurd 4.9 yards per attempt... The Vikings, who lost Adrian Peterson to injury, are averaging just 3.2 rushing first downs per game, which is less than Miami... Matt Ryan is currently averaging an insane 10.1 yards per pass attempt.