Angelique’s Mathematical Guide to Football Strategy: The CFB Rule of 4

Although Angelique thinks of football as just a bunch of guys running around in tights with a strange shaped ball, this guide will help her understand football better by teaching her something about the numbers (another thing she isn’t too fond of).

Whole Yards, never partial. In football, we determine the position on the field based on the 100 yard markers.  Even though the ball is placed exactly where it lands, statistically, we only count whole numbers.  So if a play results in 9.6 yards, that’s a gain of just 9 yards in the books.  And because a team needs to gain 10 yards to get a first down, even 9.9 yards is not good enough.

Football 101 (The Basics):  As a reminder, each team is given a series of four downs on offense in which they need to go at least 10 yards to reach a first down (or score).  If they haven’t achieved 10 yards on the first three tries, a team typically chooses to punt the ball to the other team. Why do they do this instead of using their fourth try? Because kicking the ball often gives them much better field position and theoretically will move the ball closer to their opponent’s goal line. There are some instances where punting isn’t the right solution due to the already close proximity to the other team’s goal line, the lack of time in the game and/or the need to use the 4th down to try and score.

Although we love to see the big plays and the media especially gets excited when there are plays that go for more than 20 yards (in fact, ESPN has their own “CFB Rule of 20” as seen in their many articles on the topic) the fact is that those big plays aren’t necessary to win.  A team that is disciplined and patient with what the defense gives them only needs 3.33 yards per try to get a first down (10 divided by 3).  And because football is a game of whole numbers, we must round up to 4 yards.  Otherwise, if we rounded down to 3 yards per try, the team would achieve just 9 yards and find themselves one yard short of the 10 yard requirement.   However, if an offense gains 4 yards on every play, they will always get a new set of downs after three tries (4 times 3 equals 12, which exceeds the 10 yard requirement) until they ultimately reach the end zone and score a touchdown.

That is why the critical number is 4.  To further demonstrate its importance, during a game, a team will have a member of their football staff who writes down all of the offensive plays, highlight those plays that result in a gain of 4 or more yards.  Likewise, their defense will have someone highlight those plays that hold opponents to less than 4 yards.

In reality, there are many combinations of things that occur during the game, including the loss of yardage.  In that case the strategy may change.  For instance, a team with a down and distance of 2nd and 12 will aim for 6 yards on the next try instead of just 4.  But the team that slowly and steadily achieves 4 yards on each play should find success on every drive.

So when Angelique is watching her team play on offense, she must see at least one play go for 4 or more yards, otherwise, they will likely be giving the ball back to their opponent.   Now 4 yards doesn’t guarantee a first down, because if they only get 4 yards once and nothing on the other tries, they will still have 6 yards remaining and will have to punt.   But without one play of at least 4 yards, they will never achieve the 10 yards they need in 3 tries (and like most teams, they will end up punting).