FIFA has spent the past three years testing its new Artificial Intelligence (AI)-based Semi-Automated Offside Technology (SAOT.) It has now been approved for use at the World Cup in Qatar in November, but bar a fleeting appearance at the Club World Cup in February no one really knew what to expect.
So the curtain has now been pulled back and we know a lot more about FIFA's flagship VAR project. So how will it work, what are the good points and where will fans still be left feeling frustrated?
Why did VAR offside need to change?
Long delays, perceived inaccuracies and a lack of confidence in the system among fans, players and coaches. And that's just for starters.
Scepticism also comes from the poor visualisation of decisions, with lines placed on the pitch which cannot replace a person's own perspective of an offside decision on a camera angle. A player may look onside, but the technology says they are offside.
So, what problems did FIFA hope to solve?
Firstly, selecting the exact point the ball is touched by the passer cannot be determined accurately because of the frame rate of TV cameras, 50 frames per second, used across all major leagues.
Secondly, the VAR manually selects the furthest forward point on both defender and attacker, which cannot be applied consistently.
AI removes all subjectivity from these two parts of the process, meaning there is no human role.
Added to this, the time taken to judge offside, in some cases up to five minutes for complex decisions, adds further frustration.
All in all, supporters don't really trust the process as it works now.
So what is Semi-Automated Offside Technology?
It's a tool to help VARs make faster and more accurate offside decisions by automatically determining the relative position of the players at the exact moment the ball is played.
"Semi-Automated Offside Technology has been developed to support the video match officials," explained Johannes Holzmuller, FIFA's director of football technology and innovation. "So, during the FIFA World Cup 2022 in Qatar, the video operations room will receive an automated alert in case of an offside situation, as well as automatically selected kick point, and automatically drawn offside line within a few seconds after the incident.
"After that the video match officials have to validate the proposed selected kick point as well as the proposed drawn offside line. The VAR communicates the final decision to the referee on the pitch."
"In terms of accuracy, it is important because when you are more accurate it's good," added Pierluigi Collina, the chairman of the FIFA referees' committee. "In terms of time, I think it's more psychological. We felt something was needed, and that's why we wanted to offer something giving a quicker answer. We are aware that football is different [from other sports] and making a decision faster was important, and that's why we worked in this direction."
How will it work?
Right now, the VAR can only use the broadcast TV cameras to make an offside decision. With SAOT, bespoke cameras will be installed under the roof of the stadium. These cameras provide optimal tracking for all 22 players, recording data points to calculate their exact position on the pitch. The 29 data points are on all limbs and extremities that are relevant for an offside decision -- including the upper arm, toes, knees and head -- so the system knows the exact position of a player at any given moment.
The official World Cup match ball, the Adidas "Al Rihla," will be fitted with a sensor that sends data 500 times a second, allowing a more precise detection of the kick point than using conventional camera frames (limited to 50 frames a second).
All player and ball data is processed in real time by AI, which triggers an alert to the VAR when an offside has been detected. The VAR must then validate that the kick point and offside line are accurate, and then inform the referee who can confirm the decision.
"We will implement in each World Cup stadium, 12 dedicated optical tracking cameras," Holzmuller said. "All these cameras are working together, and 100 percent synchronised. In addition to that, the official match ball will have a connected ball technology. A new Adidas suspension system houses a 500 hertz IMU [inertial measurement unit] sensor in the centre of the ball.
"This information is transmitted via antennas inside the stadium to the video operations room. In order that the system can detect precisely the offside position, the optical tracking system is collecting 29 data points, and this will happen 50 times per second.
"The IMU sensor inside the ball will provide a ball data stream than is nothing more than the acceleration data of the ball in multiple axis. We will get an automated detection of a very accurate kick point, which is especially important in very close and very tight offside situations.
"We are combining the different data sets by applying Artificial Intelligence, and this automated alert is then appearing on a timeline inside the video operations room. This is happening immediately, within a few seconds. But then of course in addition there's the manual validation process by the video match officials to make sure that the data and everything is correct."
More accurate? So are we going back to 'toenail offsides'?
Collina firmly believes that offside means offside, no matter how marginal. So unfortunately the answer is, "yes."
This was always the fear when FIFA spoke of developing a more accurate system. Right now, VAR offside has a tolerance level, or "benefit of the doubt," due to flaws in the process -- such as accuracy and how a decision is presented to fans.
That "benefit of the doubt" is to be removed, with decisions based upon the result delivered to the VAR.
"The objective is to have a very accurate technology, something similar to goal-line technology which offers a very high accuracy," Collina explained. "The goal-line technology is praised by everybody for its accuracy. So if the ball did, or didn't cross the goal line by very few millimetres, and the technology proves it, everyone is happy and everyone praises the technology for the very good answer provided.
"It should be the same for the Semi-Automated Offside Technology, which provides the evidence that a player was offside or onside in a very accurate manner. This technology should be praised as well.
"I don't see any difference between certifying that a goal was scored or not, or certifying that a player was in an onside or offside position."
Collina's view is that FIFA has developed a system as accurate as goal-line technology. Fans trust goal-line technology. So fans must also trust semi-automated offside.
But it's not that simple. The ball crossing the line is viewed as a binary decision by supporters. Offside isn't, and fans don't like the close, marginal calls. Collina is confident that decisions will be accepted, but the visualisation element is going to have to do a lot of the heavy lifting.
Hmm, so how can we tell a player really is offside?
Ok, you've read about the bad news ... now this is the good news.
This is as important as any other part of this project. It was incredibly difficult for fans to visualise offside decisions, and now they will be able to effectively move in line with the assistant referee through.
Much like goal-line technology, a 3D animation is created which will be shown at the stadium and on TV. However, this won't be at the moment a decision is made, but at the next stoppage in play after the referee has signalled the decision.
The exact point on the attacker which is deemed offside will be highlighted, and a simulation will then move in line with the players.
"We use the same elements to generate a 3D animation because we want to provide the best possible perspective to the football fans," Holzmuller added. "I think we all agree, especially for tight offside decisions, sometimes it's quite difficult to say if a player was offside or not.
"The replay shows the exact position of the players at the moment the ball was played, and the 3D animation will be shared on the giant screen in the stadium and on TV."
How long will this take?
More good news!
FIFA says that right now the average time for a VAR offside decision to be made, across all competitions globally, is 70 seconds. With the new technology, FIFA believes it can get this down to 25 seconds.
Twenty-five seconds is probably longer than those who had attended briefings through the trial process were expecting, but it still means that the majority of decisions should be reached during a goal celebration and may limit the occasions when players and fans have to stand around waiting for the outcome.
As 25 seconds is an average, there will be many occasions when it's quicker for the more obvious offside calls.
So no more long delays?
They will certainly be rare, because SAOT means the VAR won't have to go through the process of setting up the decision.
However, there will be occasions when there are subjective elements to a decision. Is a player interfering with play? Has there been a "deliberate play" of the ball by the defender? Is an attacker in the line of vision of the goalkeeper? Those decisions, and others with multiple offside elements, will take longer.
Great, so fans can celebrate goals again?
Could we get back to a situation whereby the first thought in a fan's mind is no longer the fear of a goal being disallowed or subjected to a lengthy check? With the new technology, that's part of the plan.
It will depend if 25 seconds is enough to give fans the confidence for their spontaneous goal celebrations. Speeding up the process will certainly help, but SAOT might not be the ultimate fix for one of VAR's major issues.
Even with the tolerance level added to VAR offside last season, 44 of the 120 VAR overturns (37%) in the Premier League involved offside. And of the 43 goals disallowed, 32 were for offside (73%). But that only scratches the surface. All goals and penalty decisions have had to be checked for offside.
It still means the vast majority of decisions are subject to offside checks. That it will get quicker is great, but will it be quick enough?
That said, many checks should take place in the background without any impact. We can only really judge the psychological impact on supporters once we've seen it in action.
What about the delayed offside flag?
Sorry, more bad news incoming ...
There had been a lot of talk over the past year of decisions being made in a matter of seconds. While it's true SAOT can work this out quickly, the time required for the VAR to validate decisions means that we haven't seen the end of the delayed offside flag.
It's the payoff between the automated part, and the manual assessment, resulting in the semi-automation.
"I heard of four or five seconds to get the offside decision," Collina said. "We will decrease from an average of 70 seconds to 20 or 25. It might be less when the offside incident is quite easy buy certainly we can't get an answer in four or five seconds. This is definitely a wrong expectation. It will be faster, it will be more accurate. These are the objectives."
There is a little bit of light, though it is unrelated to SAOT and is a general update to protocol. Assistant referees at the World Cup will be told not to exaggerate in delaying the flag when the offside is obvious -- and all fans want to see more of that.
Will SAOT be used for all offside decisions?
The technology provides for all potential offsides to be alerted to the VAR. However, this information is only be validated and communicated to the referee on pitch in case of one of the defined match-changing moments covered by VAR -- goals, penalties and red cards.
So if an offside is detected before a corner or a free kick, which hasn't been flagged by the assistant referee, the VAR will not alert the referee and offside will not be penalised.
When will we see it in the Champions League and Premier League?
UEFA announced it would start using SAOT for the UEFA Super Cup in August 2022, and then throughout the Champions League. We had been expecting the full debut to come at the World Cup.
But it's going to take a bit longer for the domestic leagues to get SAOT.
The Premier League, and other top leagues, are going to have to wait until the 2023-24 season before it arrives.
One issue is that an additional VAR operator (not a referee or assistant) will be required to monitor the process, which along with the additional cameras will result in more expense for leagues.
So are the "robots" taking over?
It's a phrase Collina hates, because at its heart SAOT still requires the officials on the pitch to make a decision, and then for the VAR to validate what the technology says.
"We have heard about robot referees and similar things," Collina added. "I understand that sometimes this is very good for headlines, but this is not the case.
"The match officials are still involved in the decision-making process, because the semi-automated offside gives an answer only when a player who was in an offside position plays the ball. In other words, the assessment of interfering with an opponent remains the match officials' responsibility. "
Will VAR offside ever be fully automated?
Arsene Wenger, FIFA's chief of global football development, has said he wants the offside decision to go straight from the technology to the linesman, and cut out the VAR. But Collina has previously ruled that out.
"Goal-line technology clarifies black-and-white decisions as there is only the ball and the line, and for this reason it was quite easy to find a fully automated solution," Collina said last year in a separate interview. "In an offside incident, the decision is taken after having analysed not only the position of players, but also their involvement in the play.
"Technology, today or tomorrow, can draw a line but the assessment of interfering with play, or with an opponent, remains in referees' hands. The involvement of the referees in the assessment of offside remains crucial and final."