Advanced NFL Stats has their weekly efficiency rankings which use offensive and defensive statistical categories that correspond the most with winning (Passing yards per attempt, run success rate, turnovers, etc.)
The Falcons currently sit 10th overall, after being as high as 4th after the first 3 weeks.
Namely because their passing attack has fallen off the past 3 games, and so has the pass defense. The Falcons have maintained their poor run offense and run defense.
http://www.advancednflstats.com/2012/10 ... eek-7.html