Commentary

Comparing the QB class of 2004

Originally Published: January 8, 2009
By Aaron Schatz | Football Outsiders
Because Eli Manning, Philip Rivers, and Ben Roethlisberger were chosen together at the top of the 2004 draft, they will always be compared to each other. With all three leading their teams to the playoffs and taking the field this weekend, we wanted to look at their career paths -- by looking at the most similar quarterbacks in recent NFL history.

To do that, we're using similarity scores, an idea first introduced by Bill James to compare baseball players to other baseball players from the past. They aren't a perfect measurement by any means -- because similarity scores compare standard statistics like yards and touchdowns, they are subject to all kinds of biases from strength of schedule to the quality of each player's offensive line. Nevertheless, they're fun to play with and they tell you a little bit about whether a player is good, bad, or just unique. You can find the equations for Football Outsiders similarity scores here. The most recent season is listed, but comparisons are based on three-year career spans. Of course, since there are only so many successful quarterbacks around age 27, many of the same players show up as similar for more than one player.

Note that we only compare players since 1978, the year passing rules were liberalized, and the strike years of 1982 and 1987 are pro-rated to 16 games.

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