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These rankings factor in several major attributes for the quarterback position.

Personal observation and opinion play a key role. A general section for film-review grades form a foundation, but the output of these quarterbacks' most recent performances is what really sends them flying up and down the rankings each week.

Wins also give quarterbacks a slight boost in addition to their individual performances. The statistics used to help determine the ranking system are pulled from ESPN.com, NFL.com and Pro Football Focus (subscription required), unless stated otherwise.

Stats that are factored in include passer rating, completion percentage, yards per pass, rushing yards per game, touchdown-to-interception ratio, fumbles lost and wins.

As the season moves on, the weighted influence from last year's output will be reduced by 25 percent each week.

When more than one quarterback plays for a team in one game, the quarterback with the most passing attempts is featured in the slide.

Note: Total QBR is a scoring system that assesses everything a quarterback does on the field. It is explained further on ESPN.com.

Also, Pro Football Focus grades every single play of the season to generate a cumulative point total, which weighs into the metric as well.