az1965 said:
If this is the criteria used for power rankings, not that I care about these rankings, then Cardinals should have been in the top 10 last year...
Those aren't the criteria (the power rankings are on SI, the individual unit rankings are on Fox).
Those individual unit rankings are based on something called DVOA, and explained fully on the Football Outsiders site (
http://www.footballoutsiders.com/methods.php). In brief, "The majority of the ratings featured on FootballOutsiders.com are based on
DVOA, or Defense-adjusted Value Over Average. DVOA breaks down every single play of the season to see how much success offensive players achieved in each specific situation compared to the league average in that situation, adjusted for the strength of the opponent."
It's not a ranking of mere yards (like the NFL official rankings in which Arizona was in the top 10 in both offense and defense). It is some weird, proprietary formula that analyzes each play. E.g., a gain of 7 yards on 3rd and 13 is worth less than a gain of 5 yards on 3rd and 2.
It's far from accepted in the industry and I know of no other site besides Fox and Football Outsiders that uses it. It's basically an attempt to bring sabermetrics into football.