Over at Igglesblitz today, Tommy Lawlor mentioned that QB play and coaching are much more important than people realize, specifically citing the Packers defensive performance and record for 2010 and 2011.  Basically, the defense got A LOT worse while the record got better.

Here’s the link.

I figured I’d add some stats to the point to further illustrate it, because it’s both true and very important.  Unable to quantify coaching, we’ll focus on the QB.

Here are the charts for both Passer Rating vs. Wins and Yards Allowed vs. Wins.

If you look at the slope of both lines (really the absolute value of each), its clear the above slope is much greater, hence a greater correlation.  Note: Tried my best to un-bias the effects of the different scales so it’d be visually clear.  Here are the correlation values:

Passer Rating:  .67

Yards Allowed: -.376

This is particularly relevant given the Eagles current situation, with QB uncertainty and a defense in need of serious upgrades (or significant improvement in current players).  In general, the play of Vick/Foles/Rookie? will be MUCH more important than the performance of the defense next year.

Another somewhat counterintuitive truth (at least regarding the magnitude of the difference in importance).  It also means the Eagles could use this draft, free agency, and scheme change to engineer a dramatic defensive improvement and still end up out of contention if the QB play isn’t good.