Fan Bias

Inspired by the Woodman, I’ve decided to concoct my own statistically-based NFL power rankings. We’ve all seen the various power rankings put out by mainstream media experts. But, I’m under the impression that they are very subjective. So, why not try to create an objective ranking that not only tells you how a team has done in the past but also might have some predictive value.

Such a ranking becomes more effective with more data, so it’d be pointless to try to do one early in the season. However, given that the 2009 NFL season is now seven weeks old, I figured let’s give this a shot.

In order to calculate the rankings, I used various team statistical measures (which I’ll get into in just a moment) provided by NFL.com. One caveat though. Because of bye weeks, there’s a slight inconsistency because some stats are based on season totals and thus teams that have played more games may benefit in some cases and lose out in others. (And note that I may tweak the formula over time in an attempt to refine these rankings.)

The stats I used were turnover differential, total penalty yardage, average rush yards per game, total sacks allowed, average rush yards allowed per game, and total sacks forced.

Why?

Here’s my rationale: turnovers and penalties give us an indication of how many mistakes a team makes or how careful they are over the course of a game. Rush yards and sacks allowed give us an indication as to how good the offensive line is while rush yards allowed and sacks forced tell us about the defensive line. I’m a firm believer that success in the NFL starts on both lines, in the trenches. Whether a team is a passing team or a running team. Whether a team wants to stop the run or defend the pass. And, I believe that with talent fairly evenly dispersed throughout the league, the difference between winning and losing often comes down to limiting mistakes.

With that said, here are my NFL power rankings for week 7:

1. Denver Broncos
2. Philadelphia Eagles
3. New Orleans Saints
4. Miami Dolphins
5. Indianapolis Colts
6. Minnesota Vikings
7. Cincinnati Bengals
8. Baltimore Ravens
9. New York Giants
10. New England Patriots
11. Atlanta Falcons
12. Jacksonville Jaguars
13. Green Bay Packers
14. Tennessee Titans
15. Arizona Cardinals
16. Pittsburgh Steelers
17. Dallas Cowboys
18. Seattle Seahawks
19. San Diego Chargers
20. San Francisco 49ers
21. Carolina Panthers
22. Chicago Bears
23. New York Jets
24. Houston Texans
25. Oakland Raiders
26. Buffalo Bills
27. Tampa Bay Buccaneers
28. Washington Redskins
29. St. Louis Rams
30. Detroit Lions
31. Kansas City Chiefs
32. Cleveland Browns

What I like about this statistically-based set of rankings is that they are an attempt to go beyond the records. Because of that, although I generally think the rankings tend to correlate with the records, you’ll see some teams that have over-performed or under-performed relative to what the statistics say they should have done.

For example, Philadelphia (4-2) and Tennessee (0-6) are examples of teams that are underperforming relative to their power rankings. In Philadelphia’s case, their offensive line stats are middle of the pack but their d-line and turnover differential are helping them overcome this deficiency. The Eagles are not doing very well in avoiding penalties, though.

A team that’s overperforming is Pittsburgh (5-2). The stats say this is a middle of the pack team, but the Steelers are atop the AFC North for now.

What will be interesting to watch is how these rankings change with time and whether the real records slowly move to reflect what the stats are showing us. In the end, there’s more to football than just stats — you can’t measure luck, grit, heart, and other intangibles. On the other hand, stats also serve as a measure of how teams generally perform and barring major injuries or some drastic mid-season change I believe the power rankings will be fairly consistent from week to week.

Whether these power rankings have any predictive value also remains to be seen. I’ll be posting my predictions for week 8 NFL games based on these rankings soon. Let’s see what happens when the athletes actually play the games on Sunday and Monday.