Even though quarterback efficiency rating -- a combination of each player's attempts, completions, yards, interceptions and touchdowns -- provides a good, broad indication of a passer's performance, it isn't a perfect statistic by any means. Yes, it's worth noting that eight of last season's 10 BCS bowl teams were led by a signal-caller ranked in the top 20 of the QB efficiency rating category, but the stat also fails to take into account the fact that many players contribute yards on the ground that are pivotal to a team's success.
There's also another significant factor lacking in traditional passer efficiency ratings: It does not account for opponents' strength. We decided to address this by doing a simple adjustment for the strength of the defenses faced by each quarterback last year.
For example, Kellen Moore of the Boise State Broncos posted the nation's best rating last season -- 182.6 -- and went up against a slate of opponents that surrendered an average rating of only of 131.8. Subtracting the two ratings produced a difference of 50.8, second best in the country behind Cam Newton of the Auburn Tigers (therefore making Moore the top returning QB in adjusted efficiency rating). We ran the same calculations for every top-60 quarterback in 2010 for each game played, substituting below-average defensive ratings estimates for FCS opponents.
Our results not only gave us a good idea of which top QBs did the best against top competition, but it also brought to light four quarterbacks whose overall statistical profiles improved dramatically when adjusting for opponents' strength. In other words, these five QBs may have flown a bit further under the radar than they should have last season, and could be in for breakout years in 2011.