Pro Football Focus

Similarly, an interception may be graded differently if it is tipped by a wide receiver or thrown directly to a defender.

These grades appear in many areas of NFL media, including NBC Sunday Night Football player introductions.

[1] In watching every game, PFF is also able to record information and create data that is typically unavailable.

[1] PFF claims to cover every player on every play of every game at the NFL and major college football levels and creates advanced statistics based on the information gleaned from this.

As such, the 0–100 Player Grades are not truly quantitative and could be seen as being prone to bias, poor sample sizing, or other issues.