Pro Football Focus

Pro Football Focus (also written as ProFootballFocus, and often referred to by its initials, PFF) is a website published by PFF Analysis Ltd. that focuses on thorough analysis of the National Football League (NFL) in the United States. Beyond posting the standard NFL statistics for evaluating players, PFF produces numerical grades for teams and players by watching and grading every player on every play.

History
Based in the UK, PFF was founded by Neil Hornsby. Dissatisfied with some limitations of standard statistics, Hornsby began grading players in 2004. The staff gradually expanded over next few years, and the site was launched in 2007. The 2008 season is the first season for which PFF has complete data. As of the 2011 season, PFF provides customized data to five NFL teams, along with a number of agents, media and NFL players.

Methodology
PFF grades every NFL player's every play on a scale of -2 to +2 using half point increments. The grades are based on context and performance. A 4 yard run that gains a first down after two broken tackles will receive a better grade than a 4 yard run on third-and-5 where the ball carrier does nothing more than expected. A quarterback who makes good pass that a receiver tips into the arms of a defender will not receive a negative grade, despite the negative result.

Furthermore, grades are separated by play type. Beyond just an overall grade, an offensive lineman receives one grade for pass blocking and one for run blocking. The average grade is meant to be zero, and raw grades are normalized.

In watching every game, PFF is also able to record information and create data that is typically unavailable. One example is how frequently individual offensive linemen yield pressure.