Four games may not seem like much of a sample, but in the reality of the 16-game NFL, it is a key number. Not only does that represent the quarter pole for the season, but when teams break down film to prep for upcoming games, they scrutinize their opponents' previous four games. It's a rubric I've followed in my career and as an analyst, and I'm going to use it to help guide my QB Big Board.

This ranking is not an end-all-be-all, permanent evaluation. Guys will improve -- and regress -- and that movement will be represented on this ranking every four weeks. What this QB Big Board does is combine a quarterback's historical performance with how he is playing at a certain time of the season to form a ranking of the NFL's top quarterbacks at that moment.

There are a few changes to my previous list, including how I generated it. Last offseason, I watched every throw of every NFL quarterback from 2011 to generate my initial rankings. Due to time constraints, I can't make that same claim now. Rest assured, though, that this list is the product of regular film study from the NFL Films offices each week.