Prisms shed light on soccer blunders

17 Jun 2002

New soccer system promises to make offside mistakes a thing of the past.

Offside rule

Any soccer fan will tell you that assistant referees, who have the responsibility of judging offside, often make mistakes. However, a Norwegian-based company called Reference Point System (RPS) has designed a system that promises to help assistant referees judge offside in soccer matches with greater accuracy.

About to trial across the UK, the system is based on a series of red, prismatic lights that are aligned at 120 cm intervals along the touchlines of the soccer pitch. Each light acts as a reference point for the assistant referee, who can only see the light when standing directly opposite it. RPS hopes that by using these lights, assistant referees can make sure they have a perpendicular view across the pitch, and optimize their judgement in an offside situation.

Thomas Donsig, RPS's managing director, says that the company made its first breakthrough when it realized that the positioning of an assistant referee was crucial to offside decisions. In the past, the "speed" of the game has been blamed for wrong judgements.

"Optical trickery - such as a train track disappearing into the distance when you look along it - makes it almost impossible for humans to pick out a straight line across a 70 meter pitch," he explained. "We realized that it is key for the referee to be in the right position to judge offside."

Studies made by scientists at Vrije University in the Netherlands (see Nature 404 p33), have since confirmed RPS's thoughts, and the company is now keen to bring the system to the UK. Preparing for trials across the UK, Donsig is convinced that soccer fans will love the system and he also hopes that it will bring players and referees closer together.

"Tests in Norway have already shown that when assistant referees use the prism system, [offside mistakes] are reduced by up to 50%," said Donsig. "International Football Federation Association ( FIFA) has agreed that the system does not interfere with the game, so we hope to show assistant referees that they can use the system with confidence."