Old formula: Winning Percentage (1/3), Margin per victory (1/3), Yardage Margin (1/3)
old youtube video explaining it here ---> http://www.youtube.com/watch?v=ixwDCgFs-W4
New Formula: Winning Percentage (4/7), Margin per victory (2/7), Yardage Margin (1/7)
The whole point of ranking NFL teams originally was to reward lesser known teams that had great stats with no championships. Now, I've stressed more importance on WINS and points and saved my yardage stats more for handicapping games (61% in 2010).
Please visit my site soon to see the changes. http://www.nflranking.net/