Leading and Trailing the Play
Normally, each official moves to their right ahead of the play – The Lead Official, and to their left behind the play – The Trail Official. As the ball is returned over, the trail becomes lead and the lead becomes trail.
The Lead Official
Lead is in front of the play and on the baseline.
Primarily watches the movements of players away from the ball.
The Trail Official
Follows the play up the court.
Primarily watches the ball and the players around it.
Officials must assist each other, sandwiching the play between the two referees. There are no exclusive areas of responsibility.