Football analytics glossary and definitions

Understand the football analytics terms and metrics used in Arrowhead Pride articles about the Kansas City Chiefs

Metrics used by Next Gen Stats

Passing

• Air Yards is the vertical distance from the line of scrimmage to where the ball is (or would be) caught. Passes thrown to behind the line of scrimmage are negative values — and when applicable, the depth of the end zone is included.
• Aggressiveness Percentage (Agr%) is the number of passing attempts made into tight coverage (where there is a defender within one yard of the receiver when the pass arrives) divided by the total number of attempts.
• Completed Air Yards (CAY) is the average Air Yards for completed passes.
• Completion Percentage Above Expectation (+/-): A passer’s actual completion percentage compared to their Expected Completion Percentage.
• Completion Probability (CP%) is the probability a pass will be completed. It is based on many factors — including the receiver’s separation from the nearest defender, where the receiver is on the field, the quarterback’s separation from the nearest pass rusher at the time of the throw — and more.
• Expected Completion Percentage (xCP%) uses a passer’s Completion Probability on every play to determine what a passer’s completion percentage is expected to be.
• Intended Air Yards (IAY) is the average Air Yards for all pass attempts.
• Time to Throw (T-t-T) is the average time between the snap and the throw on every pass attempt. Sacks are excluded.

Receiving

• Average Targeted Air Yards (TAY) is the average passing Air Yards per target for the receiver. This stat indicates how far downfield they are being targeted on average.
• % Share of Team’s Air Yards (TAY%) is the receiver’s total intended Air Yards (all attempts) divided by the team’s total intended Air Yards. This represents how much of a team’s deep yards the player accounts for.
• Cushion (Csh) is the distance (in yards) measured between a pass-catcher and the defender they’re lined up against at the time of snap on all targets.
• Expected Yards After Catch (xYC) is the expected yards after the catch, based on numerous factors using tracking data such as how open the receiver is, how fast they’re traveling, how many defenders/blockers are in space, etc.
• Separation (Sep) is the distance (in yards) measured between a pass-catcher and the nearest defender at the time of catch or incompletion.
• Yards After Catch (YC/R) is the yards gained after catch by a receiver divided by the number of receptions.
• YAC Above Expectation (+/-) A receiver’s actual yards after the catch compared to their Expected Yards After Catch.

Rushing

• 8+ Defenders in the Box (8+D%) is the percentage of plays in which a rusher faces eight or more defenders in the box.
• Average Time Behind Line of Scrimmage (TLOS) is the average amount of time a ball carrier has the ball before crossing the line of scrimmage.
• Efficiency (EFF) is the number of yards a player ran as a ball carrier divided by the rushing yards gained. The lower the number, the more the player is a North/South runner.
• Expected Rushing Yards (xRY) is the number of rushing yards a ball carrier expected to gain on a given carry, based on their relative location, speed and direction of blockers and defenders.
• Rushing Yards Over Expected (RYOE) is the difference between actual rushing yards and Expected Rushing Yards on an individual play or series of plays.
• Rushing Yards Over Expected Per Attempt (RYOE/Att) is the difference between actual rushing yards and Expected Rushing Yards, then divided by the number of rushing attempts.

Passing defense

• Ball Hawk Percentage (Hawk%) is the defender’s passes defensed and intercepted divided by targets.
• Average Separation (Avg. Sep) is a defender’s average distance from receiver when pass arrives.
• Catch Percentage (Catch%) is the Opponent’s completion percentage when defender is targeted.
• Catch Percentage Over Expected (CROE%) is the Catch Percentage compared to opponent’s completion percentage.
• Coverage Expected Points Added (Cov. EPA) is Expected Points Added when a defender is targeted.
• Tight Window Percentage (TW%) is the percentage of throws attempted into a tight window (defender within half a yard of the receiver) when defender is targeted.

Other advanced metrics

• Expected Points (EP) is based on the idea that not all yards gained are of equal value. For example: gaining five yards on a third-and-4 — thereby moving the chains — is different than gaining five yards on a second-and-12, which just leads to third down. EP is calculated by comparing the situation — down, distance and field position — at the start of the play to the situation at the end of the play.
• Expected Points Added (EPA) is a measure of how well a team performs relative to expectation. For example: a team starts a drive on the opponent’s 40-yard line. Its expected points — the average number of points scored by a team from that spot — would be about 2. If the team then scores a field goal its EPA is found by subtracting its expected points (2) from how the points scored (3). That drive would then have an EPA of 1. But if the team doesn’t score on the drive, it would have an EPA of minus 2.