Glossary

How much value each play produced, relative to expectation.

• AltitudeThe MockingBoard weekly score for QB, RB, WR, and TE, shown as a historical percentile with named bands from Grounded to Soaring.
• Completion percentageCompletions divided by pass attempts. Simple, familiar, and blind to how hard the throws were.
• CPOE (Completion Percentage Over Expected)Completion percentage minus what an average passer would complete on the same throws, given depth, location, and situation.
• EPA (Expected Points Added)How many expected points a single play added or removed, based on how it changed the down, distance, and field position.
• EPA per dropbackExpected points added per dropback, sacks and scrambles included. The best public passing efficiency number.
• EPA per playExpected points added divided by offensive snaps. The best single-number measure of how good an offense or defense is.
• Success rateThe share of plays that gained positive expected points. Answers "how often does this work" instead of "how big are the wins".
• Yards per carryRushing yards divided by carries. Famously noisy, famously quoted, and usually the wrong tool for the question.

How much happened. The denominators that give rates meaning.

• Air yardsHow far the ball traveled past the line of scrimmage on a throw, caught or not. The intended depth of the passing game.
• Attempts and dropbacksTwo ways to count passing volume. Attempts count throws; dropbacks also count sacks and scrambles, the plays attempts hide.
• YAC (Yards After Catch)Yards gained by the receiver after securing the catch. The half of receiving yards the throw did not cover.

The closed vocabulary of game contexts behind every split.

• Red zoneSnaps inside the opponent's 20 yard line, where the field shrinks and touchdowns are decided.
• Score stateWhether the offense was leading, trailing, or tied at the snap. The context that quietly drives play-calling and pads stats.
• Shotgun and no-huddleUsage buckets for formation and tempo, snaps taken from shotgun and snaps run without a huddle.
• Two minute drillSnaps in the final two minutes of either half, when clock management bends every play call.

How the numbers are processed and presented, honestly.

• League baselineThe league-wide average for a metric in a given season, the honest zero point every comparison should start from.
• Rolling meanAn average over the last few weeks instead of one week, trading a little lag for a lot less noise.