They are senior referees that have been given additional training in order to be able to objectively evaluate other referees and give them useful feedback in order to improve.
Originally, soccer was played under the supervision of team captains, and the captains would have to agree on any points related to the game, such as when a goal is scored, a foul is committed, and...
The referee must send the player off for violent conduct and write up what happened in the game report. If the referee feels at any moment that his safety is in continuing jeopardy, the game must be...
You take classes to become a referee yourself, work hard at it until you are a higher grade, then you go to more classes to become a referee assessor. Only then is one qualified to properly evaluate...