Online tool for assistant referees at Euro 2016

The decisions of the assistant referees are crucial in football. Offside or no offside, means often also goal or no goal. Koen Put developed an online tool for assistant referees. The tool is also used by the assistant referees that are active during the European Championships in France. European referee boss Pierluigi Collina requested earlier this year to prepare the Euro 2016 referees perfectly. “A good moment to apply my tool and research in real situations”, says Put. “I am convinced the tool can make the difference in the field of observing and decisions”, he adds in an interview with Dutch Referee Blog about his research, the online tool for assistant referees and the European Championships in France.

Koen Put during referee training session

Preparation for Euro 2016

For a researcher scientific publications are important, but to put things in practice for the Euro 2016 referees is of course a great challenge. The online tool was an important tool in the preparation for the assistant referees. Since April they get to see twenty new  clips each week. At the start of the tournament they have watched at least six sets with twenty clips. The advice of the researchers is to watch every set at least five times and take the right decisions every time. “That means they have made six to seven hundred offside decisions right before the start of the tournament. They need way too much games to reach such numbers in real situations.” The researchers of Leuven University in Belgium process the results of the tests and report them to the refereeing officers at Uefa and the experts in assistant refereeing. “The feedback is open and assistants can see how many mistakes they made and what has improved”, says Put.

Research on decisions of assistants

In 2011 Put started is PhD research under supervision of Werner Helsen, professer at Leuven University and the fitness expert for referees at Uefa. A five year project sponsored by the lab called “Waarnemen en Presteren”, that has a tradition in research about refereeing. That – in English – Perception and Performance research unit is part of the Movement Control & Neuroplasticity Research Group of the Department of Kinesiology.

Koen Put

Put’s research focused completely on improving the perception and decision processes by assistant referees. “We did our research in close collaboration with Uefa”, says the researcher. “We noticed that assistants could barely practice on perceiving offside, while that is their main business. That what they have to excel in during a football game. An offside situation only happens five to ten times a game and an assistant directly has to decide it correctly.”

The most important goal for Put was: offer the right exercises and practice for assistants. He developed the online training tool ‘Perception4Perfection’, whereby assistants are shown offside situations which they have to judge. The most important question for the researchers is of course: will it be useful during a real game in actual practice? “It turned out that off-field training certainly influenced the achievements on the pitch. We actually saw 20-25% better decisions by assistant referees in Blegum who use the tool on regular basis. We found something that worked to improve the perception of assistant referees.”

Operation of the online tool for assistant referees

Assistant referees get a logon and password for the tool. On that platform they can find hundres of video clips that vary in different type of attacks and difficulty level of the decision. The most important question they need to answer: offside or not?

Online tool for assitant referees

During the second task the participants will see five different photo’s. They need to indicate what the most correct frame is at the moment of the pass. After that a slow motion of the situation follows and they will see a freezed frame at the moment of the pass.

Beginner versus expert

The tool is suitable for beginning and more experienced AR’s. “Our research proved that beginning referees made lot of flag errors”, says Put. “Attackers are still too quickly wrongly flagged off. Due to the exercises people learn to suppress their tendency to flag. That’s how the accuracy of their decisions increases. The more experienced referees should not get the tendency to flag too little.”

The tool has been improved over time. One of the developments is adapting the speed of the clips. The goal is to create video’s that can be compared with the fast games from big competitions like the Champions League and Europa League, but also for the level at which refs from the talent group act. “Our conclusion: the top assistants from uefa had more problems with a frame rate of 75% than when the clips were played faster. With situations at high speed they were more accurate. We give the top referees now clips at their level. That way we can adapt the clips to the level of the assistant referee.”

Development of the tool: clips in 3D

Put is not satisfied with a tool that works fine. He wants to make an even better tool and checks if the clips are good enough to simulate the real perception. A possible improvement: clips in 3D. “The depth perception is very important for assistants”, explains Put. The assistants need to come to their lab and have to wear 3D glasses. “And it works. Assistants are more involved with situations. So that’s a good innovation.”

But can it get closer to reality?

The researcher of Leuven University placed 30 metres of rails next to the sideline with a camera on it that followed the secondlast defender. The videos were shot at eye level of the AR. “That is super for them.”

Viideo camera with second last defender

Referee support in France

Back to the European Championships in France.

Werner Helsen is head of physical support for referees during Euro 2016. He and four coaches have prepared the referees before the tournament. Koen Put is one of them. He will combine the physical part with supporting the assistant referees. When Put met the assistant referees during a previous briefing in Paris they told him they ‘really appreciated’ the tool. “I am convinced that the tool can make a difference in perception and decision making. A great addition to the refereeing system.”

During the tournament in France the referees will always have access tot he tool. “We will encourage that”, says Put. “We notice that many AR’s use the tool on match days to practice and optimize their perception.”

Put went to Paris on the 5th of June. “During the first days referees were prepared for the games. On the second match day we also used players to simulate match situations on the field. Now the tournament has begun, it’s more difficult to schedule those things, because the refereeing teams have lots of obligations before or after the games. We will take the assistants apart to focus on certain things.”

The support for football teams gets more professional every day. “That’s the same and maybe even better with referees”, assures Put.

Tips for amateur referees

Not only the referees at the Euro’s use the tool. Every football association in Europe has access to the video clips and a coordinator for assistant referees decides who will get access. But without the tool it is also possible to learn and get better in judge offside situations:

  • Check vidieo clips and judge offside yourself. That is also possible with clips on YouTube or you can watch at your local referee association.
  • Watch your own games if possible. And rewatch certain situations and observe where something goes wrong. That way you get to know what difficult situations are for you.
  • Discover your tric. “Every assistant referee has a tric. A personal precept that when there’s a certain distance between an attacker and the secondlast defender, that’s when you need to flag.”
  • Try to practice with real situations. “Very useful, but takes much time and you need to arrange all the players and instruct them.”

“Crucial for every referee is: your position needs to be perfect. That’s why physical condition is very important. You need to be at the exact line of the second last defender. That’s a basic requirement. The top refs that are active at the Euro’s, suffice to this requirement.”

Check the interview with Dutch Euro 2016 assistant referees Erwin Zeinstra and Sander van Roekel.

Assistant referees of Bjorn Kuipers

Dealing with pressure

The pressure on Euro 2016 is higher during such a big final stage tournament. “I can’t say they are resistant to it, but they definitely more resilient.” As an example he discusses the situation in the CL final. At the first goal of Real Madrid a free kick was headed forward. At the moment of the header it seems that Sergio Ramos, who scores, is just in offside position. “Such a decisions is very difficult, the player is offside with only a part of his leg.”

The tools and training sessions don’t guarantee a game without mistakes, stresses Put. “Referees remain human. But we see nowadays that 96 – 97% of the offside decisions are made correctly.”

Back to the CL final. “Right after that goal was scored there’s a similar situation. Again a very difficult call and it was made correctly. A good assistant referee forgets a previous decision he has made. He knows he have to be focused constantly to make the right call. That is the power of a top class assistant referee.

Read more from Euro 2016 referees

Signed cards by Bjorn Kuipers

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