28 April 2021

Can we (always) trust technology providers?

This blog has been viewed: 49 times

The offside rule has been part of the Laws of the game since the very start of football. Originally, it was used to give more or less benefits to the attackers / defenders.

Nowadays, it is still an interesting and challenging issue, in particular because FIFA is now considering to introduce a (semi)-automatic offside decision making technology. For the following reasons, we question if technology can (always) provide a solution as they pretend.

The last 20 years, Werner Helsen's research group has been involved quite intensively with offside research. We even developed our own software to precisely detect offside in TV footage because of parallax errors. Based on these experiences, below I provide you food for thought.

The most important limitation is the frame selection. Even in the Champions League, there is only a sampling rate of 50 Hz. There are cameras filming at 150 Hz but this is just for high definition slow motion. This means 0.02 seconds between 2 frames. A player running at 25 km/h covers 13,88 cm. This can be the difference between onside and offside. As a result, this margin of error needs to be considered to detect ‘real’ offsides, because everything below is questionable.

Another limitation is the offside line that is 5 cm wide. If there is overlap between the lines of the second defender and the attacker, then technology cannot provide any accuracy. In this case, what is the best option? Give the benefit to the decision of the AR on the field? Or give the advantage to the attacker? In the Champions League there was only one such a situation, but in the Premier League there were 8 last season. In this case, technology cannot help and it is misleading to pretend that it is an accurate call.

As sport scientists, it is important to consider this margin of error. A margin of error is also considered for goal posts. FIFA accepts a 20 mm deviation per meter. At the top of the goal this can be 4 cm, which is a lot.

Therefore, the current offside rule is too complex and the margin of error too big (in combination with the importance of it and the time it takes to draw the lines). At the beginning of the VAR system, the idea was to reduce the human error, but now the wrong impression is provided as if the technology works perfectly but this is certainly not so. The time it takes and the frustration it creates may question the VAR system which is very unfortunate.

Therefore, we need to think of solutions. Some people say to only look at the feet but this does not solve the accuracy problem. Therefore, another solution may be to decide about offside if there is no overlap at all between the attacker and the second last defender. A while ago, they called it daylight in England. This idea was not fully the same, it could be easier and clearer to detect offside, even for the human eyes of the ARs. It would also lead to less discussions.

Last but not least, it would benefit the attackers and would certainly result in more goals!

Food 4 thought.

Do you want to share your opinion on this and more topics? Join the discussion in our LinkedIn community!

Can we (always) trust technology providers?

Thinking under pressure: How demanding is refereeing with respect to perception and decision making?

When watching a football game, people tend to only remember the mistakes a referee makes, however we often don't realize how many correct decisions were made before that one wrong decison. We dive into deeper detail about the accuracy of decisions of an English Premier League referee per game.

27 May 2022

Read more

Professional referee training programme

A professional referee training programme is built around match days. There are sessions to prepare for the game itself, but also a lot of attention for recovery. Werner Helsen talks us through a week of training for top match officials.

30 December 2021

Read more

How ARs train and prepare for their top games

How assistant referees (ARs) train and prepare for their games is a little different compared to the referees. Werner Helsen, Sports Scientist & Training Expert with UEFA and professor and scientist in Performance Science at KU Leuven, gives you in this story a sneak peek into their preparation.

14 December 2021

Read more

Euro 2020 referee fitness stats and training preparation: prof. Werner Helsen on fitness & freshness

This blog is written in cooperation with The Dutch Referee Blog, and talks about Werner Helsen's insights on referee fitness statistics and training preparation.

30 November 2021

Read more

Want to experience the real perspective of a VAR?

In this blog we discuss the added value VAR brings to football. You can even try to test your knowledge yourself with an example of a P4P training clip used to train UEFA VARs!

26 May 2021

Read more

What is the impact of Covid-19 on online training performance?

In this blog, we discuss the impact Covid-19, and specifically lockdown has had on participations and user scores on Perception4Perfection.

12 May 2021

Read more

To what extent is a football referee’s assessment context sensitive?

In this blog, a previous research is discussed where the level of referee judgement in different situations was investigated.

20 April 2021

Read more

How can technology be used correctly to improve decision making?

In this blog, we discuss a research that investigated the impact VAR technology has on decision making-accuracy in professional football.

30 March 2021

Read more

How can online training improve on-field offside decision making performance?

In this blog, we talk about how Perception4Perfection can play a major role in improving on-field decision-making for football officials.

23 March 2021

Read more

{{ popup_title }}

{{ popup_close_text }}

x