Refereeing high school soccer has got to be the worst part time job in the world. Only a love of the game would cause someone to put themselves up for that much abuse.
Still, there has to be some kind of rating system to identify those refs who succeed best at it. Would you coaches be willing to fill out an evaluation form after each game? Average the two teams sheets for some kind of numeric rating. Highest rated refs each year get to work playoffs with some extra money as a kicker. Just athought.
