Recently, I've received a handful of inquiries about how these rankings work. With teams like the 2-4 Chargers and 1-5 Cowboys at the top of the rankings, that's understandable. I thought it might be helpful to explain some things in plain language.
These are not 'power ratings' or my personal estimations of team strength. They're not necessarily the teams I think will make the playoffs. They are simply rankings in order of team efficiency.
I found that efficiency, more than anything else, correlates with, and is predictive of, winning. So the model focuses on net passing and running efficiency on both sides of the ball. It also considers turnover rates, such as interception per attempt and fumble per play. Penalty yards per snap is also included. All of these factors are weighted according to how well they mathematically correlate with team wins.
What makes this model unique is that it distinguishes between factors that are explanatory (telling us why teams won past games) and factors that are truly predictive (telling us why teams will win future games). For example, turnovers and turnover differential account for a very large part of why teams won previous games. But turnovers are extremely random from week to week, and teams are not consistent from one part of the season to the next. They're obviously not entirely random. (Peyton Manning will never have a 4% interception rate--3% is league average), but a very large part of the variance in interception rate can be accounted for by randomness. In other words, Eli Manning might have a 3.9% interception rate so far this year, but it's far more likely that his future games will be much closer to the league average of 3% than they will be to his current 3.9%. So factors like interception rate, which are relatively random, get heavily discounted in this model, especially early in the season.
Lastly, there is an adjustment for previous opponent strength. Once all the teams' ratings are calculated, I average up the ratings of each teams' previous opponents. Teams with tougher opponents get their rating bumped up and vice-versa.
Let's take Atlanta as an an example. They're a fairly average team statistically: 5.8 net YPA (slightly below league avg), 4.1 YPC rushing (avg), 6.4 defensive YPA (slightly worse than avg), and 4.3 YPC on defense (slightly worse than avg). One of the major reasons they are winning, however, is their turnover differential. They are tied for 4th in the NFL with a +6 giveaway/takeaway. This is primarily due to a whopping 5.6% defensive interception rate. There is virtually no way that pace can continue. History tells us their future turnover differential is far more likely to be closer to league-average than where it is now.
So statistically, the Falcons are average or slightly below, but they've been playing relatively weak opponents. They've faced PIT, ARI, NO, SF, CLV, and PHI. Of those teams, only 2 are contenders--PIT and PHI. Even NO has been surprisingly weak so far. Ultimately, you have an average but lucky performance for the Falcons, but they managed it against some pretty weak teams. So they would drop from league-average, about 17th or 18th, to where they are at 25th. They are a missed FG and a freakish (but incredible) forced fumble away from being 2-4 instead of 4-2 against an easy schedule.
Here are this week's rankings. (Click on the headers to sort.)
|RANK||TEAM||LAST WK||GWP||Opp GWP||O RANK||D RANK|
Here are each team's efficiency stats.