Football Glossary


Expected Points (EP) assigns a value to each yard line to measure the points that are expected to be scored from that down, distance, and field position. Consider: there are thousands (millions?) of drives that have started 1st-and-10 from the 25, how many points did each drive end with? Some end in 7, some 6, many 3, most 0, and a few even -2. When all of those results are averaged together, you have an expected point value for 1st-and-10 at the 25 (it's generally around 0.6 points, by the way). 

Expected Points Added (EPA) the amount of Expected Points gained (or lost) on a play. 

Havoc measures the percentage of plays where the defense recorded a sack, tackle for loss, forced a fumble, intercepted a pass or broke up a pass. It can be divided between Front 7 Havoc (TFL/FF) and DB Havoc (INT/PBU). 

Predicted Points (PP) is's specific implementation of Expected Points.

Predicted Points Added (PPA) same as EPA, using's Predicted Points model.

Usage is simply the percentage of plays on which a player was a rusher, passer, receiver, or intended receiver (targeted). Usage can then be broken down lots of ways--by down, by play type, by looking at just successful plays, filtering out garbage time, etc. It gives you a great look at how much a player is being depended on and in what situation. 

Offensive Line Stats (via Football Outsiders):


  • Line Yards per Carry: the line gets credit for rushing yardage between 0-3 yards... and 50% credit for yards 4-8.... Anything over 8 yards is quantified as a highlight opportunity, and credit goes to the runner. As with the pro definition, lost yardage still counts for 125%. (Garbage time is filtered out for all line yardage averages.)
  • Standard Downs Line Yards per Carry: The raw, unadjusted per-carry line yardage for a team on standard downs (first down, second-and-7 or fewer, third-and-4 or fewer, fourth-and-4 or fewer).
  • Passing Downs Line Yards per Carry: The same unadjusted averages for rushing on passing downs.
  • Opportunity Rate: The percentage of carries (when four yards are available) that gain at least four yards, i.e. the percentage of carries in which the line does its job, so to speak.
  • Power Success Rate: [P]ercentage of runs on third or fourth down, two yards or less to go, that achieved a first down or touchdown.
  • Stuff Rate: [P]ercentage of carries by running backs that are stopped at or before the line of scrimmage.
  • Sack Rate: Unadjusted sack rate for all non-garbage time pass attempts.
  • Standard Downs Sack Rate: Unadjusted sack rate for standard downs pass attempts.
  • Passing Downs Sack Rate: Unadjusted sack rate for passing downs pass attempts.


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