11 Personnel
11 personnel is the modern game's default grouping — one back, one tight end, three wide receivers. Why every level runs it.
11 personnel is one running back, one tight end, and three wide receivers. The first digit is the number of backs; the second is the number of tight ends. It's the most-used grouping in college and NFL football, the base of nearly every spread offense, and the personnel package that defines what a 'modern' offense looks like.
The reason 11 took over is balance. You can run inside zone, outside zone, gap schemes, and any RPO menu without changing personnel. The defense has to commit a base call that handles both 3x1 and 2x2 sets. That's a hard ask for any front.
Defenses now answer 11 personnel with nickel as the base — five DBs on the field every snap. The tight end is the swing piece. A flexed Y forces the defense into pass rules; an attached Y forces them into run rules. Smart offensive coordinators move the tight end pre-snap to flip the call.