I always shake my head when I see an otherwise well respected sports writer like Chris Price or Mike Reiss quote PFF stats. Maybe they use their data simply by default - because there is no other source for such information.
Nobody else like Elias Sports Bureau or Stats Inc. bothers to attempt to compile that kind of data most likely because they realize it would be flawed. Those big name sources for stats count things like yardage and receptions; those numbers are completely objective.
However what PFF does is not only completely subjective, the mechanism (television video rather than the coaches all-22 tape) and data collectors (amateur volunteers with no professional coaching experience) make the potential for their statistics to be flawed so high that they probably shouldn't be cited as fact by anybody for any purpose, at least not with a great big disclaimer.
I think one phenomenon that I am seeing is that because writers like Price and Reiss refer to their stats, they are assumed to be legitimate. The only thing I can think of to compare this to is when Bleacher Report first started becoming known; because they were appearing on the main page of well known sites such as CBS Sports and Fox Sports, the initial assumption was the articles there were legitimately objective, professional and factual.
As a reminder, PFF declared that David Garrard was a better quarterback than Tom Brady a year ago, and Stylz G White was a top NFL defensive lineman. PFF stats make for interesting topics of discussion, but should not be taken seriously as factual evidence of anything.
