This is the pinnacle of NFL team rankings using against the spread and straight up stats. Here we highlight the best performing teams and allow you to sort the ranking you find most valuable. The Rating Percentage Index (RPI) measures a team's strength of schedule and how a team performs against that schedule. This index considers whether a team won or lost but not the margin of the victory. More weight is given to teams playing and winning games on the road. The NFL is a pass-oriented league so it's no surprise that the Pass Rating Differential (PRD) index is an excellent indicator of a team''s success straight up. It has a positive correlation to the number of games a team wins. PRD subtracts the passer rating of a team's opponents from its own offensive passer rating. Also check out YPPA which measures how many yards teams surrender for every point allowed and YPPS which measures how efficiently teams turn yards into points.