The same down-based success standard as passing success rate, applied to a player's carries.

Inputs: Down, distance, yards gained and touchdown on plays where this player was the ball carrier.

How a player performed specifically on 3rd down plays this season -- success rate, touchdown rate, and the underlying counting stats, isolated from every other down.

Inputs: Every play on file where down = 3 and this player was involved (passer, rusher, receiver, or a tackle/sack/INT/fumble recovery on defense).

The same idea as 3rd Down Splits, isolated to 4th down plays -- the highest-leverage down in football.

Inputs: Every play on file where down = 4 and this player was involved.

How a player performed once his team's offense (or the opponent's, for a defender) reached inside the 20-yard line.

Inputs: Every play on file within 20 yards of the goal line (`distance_to_goal <= 20`) this player was involved in. COVERAGE CAVEAT: true field position is only recorded for about a third of plays leaguewide, concentrated in FBS/FCS games -- a player whose games come from a source without it will show thin or missing red-zone splits even if he played plenty of red-zone snaps. This is a gap in the underlying play-by-play data, not a sign he didn't play there.