EVIDENCE THAT YELLING AT REFEREES WORKS. This article on the fivethirtyeight website by Noah Davis and Michael Lopez describes a study which shows that “a sideline bias in the NFL is real, and itâ€™s spectacular.”
A “natural experiment” results from the fact that each football team sets up on one side of the field, across from each other. A count of calls made (penalties assessed) by referees shows that: “refs make more defensive pass interference calls on the offensive teamâ€™s sideline but more offensive holding calls on the defensive teamâ€™s sideline. Whatâ€™s more, these differences arenâ€™t uniform across the field â€” the effect only shows up on plays run, roughly, between the 32-yard lines, the same space where coaches and players are allowed to stand during play.”
The theory is that the players and coaches on the sideline near the referee who makes the call will influence the referee.