Brace yourself for some provocative Week 8 numbers. Have fun!
RATINGS COMPUTATION (must-read for newbies):
At its heart, this is a VERY simple method of calculating ratings, using only two stats. The results aren't supposed to be a perfect reflection of the real world, so don't take them too seriously! It is interesting how such a crude algorithm can be as accurate as it is, though.
Here's how the ratings are calculated. The first step is to calculate two simple stats: Points For per Game, and Points Against per Game, for each team. These two leaguewide data sets for offense & defense both conform to a "Bell Curve", or Normal Distribution, that can be graphed. Depending on where each team lies on that graph, they have a value between 0 and 1. (This isn't something pulled from thin air. It's a very common, standardized statistical analysis technique. The purpose is to more accurately measure each team's position within the population of all league teams.) You now have every team rated from 0 to 1, on offense and on defense. Add those two numbers and you've got a total rating for each team. Last, multiply by 50 to convert the ratings onto a 0-to-100 scale to make them more readable and intuitive. There you go. Simple, right?
Crazy looking numbers, you say? After kicking the Gamble-Tron 2000 and recalibrating the Frinkometer, they actually make some sense when you consider how the algorithm works.
Look at the Saints, Vikings, and Broncos. Every one of those teams is great on one side of the ball and below average on the other. Mathematically, these 3 teams cannot exceed a Power Rating of 75 as long as they remain below average on that one side of the ball. I'm not saying it's just and fair, but it IS how the math shakes out. If you remove those three turds from the punch bowl, the ratings look a lot more plausible.
Just for fun and a semi-reality check, let's look at teams ranked by Point Differential per Game (DIFF/G), instead. It's a most useful stat that correlates very highly with winning percentage.
Interesting that the Vikings and Broncos don't exactly dazzle using this yardstick, either. The 4-3 Ravens and Packers are in the top 8 using both methods as well. I'm just guessing, but I betcha Saints fans prefer this latter ranking. What a spread there!
Coming back to Power Rankings, the Ravens rose 9 spots; the Cowboys and Texans rose 6. Teams with the largest declines were the Giants, 9 slots, and Broncos, down 7.
That's all folks! Remember that this is simple, math-driven Fun With Numbers. Feedback is welcome, but please don't comment just to gripe about where your team's rated; the algorithm plays no favorites. You can download the spreadsheet here if you like playing with the numbers. Cheers!