by Jeff Anderton
After reading several articles about Passer Rating Differential being the most relevant stat correlated to winning NFL football games, I decided to see what the current year to date QBR Differentials were for the NFL. For those that don't know, QBR is the "new" rating that ESPN developed and introduced this summer(2011). ESPN was looking to build off the "traditional" passer rating formula and take into account specific things that happen during a play.
For example, a QB makes a bad pass on a 5 yard "out route" but the receiver makes amazing catch, the Defensive Back falls down, and the receiver then turns it up field for a 30 yard gain. Under the QBR system the QB would not get as many "points" for this play since he made a bad throw, the DB fell down, there were a lot of yards after the catch, and the receiver made an amazing catch. There are also factors that figure out how to differentiate between "garbage time" and clutch scenarios, taking into account the current score, time left in the game, type of defense being used(prevent defense dink and dumps score low), etc.
So with that quick background behind us, lets take a look at what I did to compile these numbers. I took the individual QBR rating for each teams opponent for every week of the year, then simply added them up and divided by games played. I then took the team's own QBR rating(what their man under center scored for the year so far) and subtracted what they "got" from what they "gave up". Nothing major here in terms of math, just some down and dirty research.
For games that involved teams who used 2 QB's I simply added both ratings together for that game and divided by 2. I realize there could be some flaws with this method if we look at it from a "weighted performance perspective", but it would be such a small variance I don't think it much matters.
Not a whole lot of suprises as most of the good teams are at the top and the bad teams are at the bottome, but still interesting to see where a few teams fell. I was surprised that the Texans and Eagles were this high, and also surprised that the Jets, Bears, Falcons and Redskins were this low. These numbers are through and including week 5 and account for teams that had a bye week already.
Team by Team QBR Differential through and including week 5 of the 2011 NFL Season