The job of a softball referee, or UMP, is to officiate the game and make sure that all rules are followed. They are responsible for making calls on the field, such as balls and strikes, and ensuring that the game is played fairly. Umpires also have the authority to eject players or coaches from the game if necessary. Umpires must be knowledgeable about the rules of the game and be able to make quick decisions in order to ensure the safety of all players.