We’ve been writing a series of articles using Pro Football Reference’s Approximate Value metric.
Approximate Value (AV) method is an attempt to put a single number on the seasonal value of a player at any position from any year (since 1950).
It’s not a perfect stat, as its creator acknowledges.
"AV is not meant to be a be-all end-all metric. Football stat lines just do not come close to capturing all the contributions of a player the way they do in baseball and basketball. If one player is a 16 and another is a 14, we can't be very confident that the 16AV player actually had a better season than the 14AV player.