What it is

A personnel grouping is a short code that tells which skill players are on the field. The first digit is the number of running backs and the second is the number of tight ends. The rest of the five skill spots are filled by wide receivers.

In a game

For example, “11 personnel” means one running back, one tight end and three wide receivers. “21 personnel” means two backs, one tight end and two wide receivers, a heavier set. “12” means one back and two tight ends.

More detail

Defenses watch the personnel carefully, because it hints at the play. A team with a heavy set is likelier to run, while three or four receivers suggest a pass. Smart offenses run both from the same grouping to keep the defense guessing.