The gameplay consists mostly of plays or “downs” starting at the line of scrimmage.
The team in possession of the ball will have four attempts to advance with it at least ten yards in order to gain a “first down” which resets the attempts back to four for the next advancement
The attacking team can score points by reaching the end zone with the ball in their possession, this is called a touchdown, Or by kicking a field goal.
However, if the first three downs are unsuccessful, the team faces a decision on what to do with their final attempt. This situation is then referred to as “4th-and-X” where X is the number of yards required.
Playing the fourth down as any other down, to try and gain the missing yards. If successful, the team will gain a new first down and be able to continue their attack (or score a touchdown if the downs have started close enough to the end zone). If unsuccessful, the opposing team will start their attacking turn from the spot where the fourth down ended.
Attempting a field goal. If successful, the team will score 3 points, the attacking turn will end and the opposing team will receive a kickoff to start their own attack. If missed, the possession is overturned to the opposing team.
Punting the ball. If the team is still too far to attempt a field goal one option is to punt the ball as far as possible from their own end-zone for the opposition to start their attacking turn.
- What’s the probability of a successful fourth down when the yards required are known?
- If the fourth down is successful, how likely is the following attacking drive to result in points scored by either a touchdown or a field goal?
- If the fourth down is unsuccessful, what are the position probabilities of the starting point of the opposing offensive drive?
- How likely is a field goal from the current position (ie. the distance from the current position to the goal posts)?
- If the field goal is missed, what are the position probabilities of the starting point of the opposing offensive drive?
- If the ball is punted, what are the position probabilities of the starting point of the opposing offensive drive?
Pride or Math?
The researchers (such as Ben Baldwin) have been running simulations on plays from the past seasons and found out that the coaches tend to be too conservative when choosing their plays.