Wednesday, September 15, 2010
Week 1 Dallas QBRD
One of the statistics I will discuss throughout the year is something I have termed 'QB Rating Differential (aka QBRD).
Here's the formula for QBRD:
Team's Offensive QB Rating - Team's Defensive QB Rating Allowed = QBRD
QBRD is a great statistic because it has a very strong statistical correlation to winning or losing in the NFL, it's simple to use, and gives an easy indication of how well a team's offense and defense is doing.
The correlation coefficient (a statistical equation that tells how strongly one statistic correlates to another statistic) is very strong, usually in the +0.8 to +0.85 range each year. So usually the higher the QBRD, the more wins a team will have. And the lower the QBRD, the less wins a team will likely have.
After week 1, Dallas QBRD is 23.9 (87.3 - 63.4).
I have taken the last six seasons of the NFL's QBRD, found the correlation coefficient and created a linear regression formula (a formula that helps predict an outcome).
The good news is that a +23.9 QBRD will predict a season with 12.18 wins.
However, take that with a grain of salt for now because it's just 1 game into the season. Come about week 10, that's when the QBRD really starts to show what a team has and their chances of making the playoffs, how well they'll do in the playoffs, etc.
The bad news is that when you 'out-QBRD' your opponent by +23.9 points and lose the game, that's a game you should've won.