Video assistant referees: Has VAR worked? What changes are needed?

After video assistant referees (VAR) were trialled at the Confederations Cup and the Under-20 World Cup, what is the verdict so far?

Referees at both tournaments were able to decide whether they wanted help from VAR, while the video referee could also suggest to the man in the middle that a decision should be reviewed.

Scottish referee Willie Collum worked as a video referee at the U20 World Cup in South Korea, and told Sky Sports about the positives, the negatives, and what needs to be tweaked ahead of potentially using the technology at the World Cup in Russia and perhaps the Premier League...

How did it work?

"It is clear that FIFA are saying that video referees are there to support the referee, but only in case of a clear refereeing error. For example, if there is a missed red card or penalty, or a case of mistaken identity [such as in the Confederations Cup when referee Wilmar Roldan initially sent off the wrong Cameroon player against Germany before consulting the VAR and getting the decision right].

"It must be a clear refereeing error before the video referee gets involved and changes a decision. As soon as an incident takes place that might be regarded as debatable then the video referee would ask the operator in the van to check an incident and start to show angles.

"The video referee then has the ability to speak to the referee and tell them they are checking an incident and also possibly to tell the referee not to restart the game so it allows as much time as possible to review the incident and make sure you come to the right decision."

How was your experience at the U20 World Cup?

"Being in the truck as a video referee is very different to being on the pitch, understandably, but there is a lot of pressure because the video referee is there to make decisions to try and improve the game and correct any major decisions.

"When a decision takes place that has to be corrected, which happened to us on several occasions in Korea, then you need to make sure you have got it right. It's not just a matter of looking at something once, you need to make sure you look at different angles to make sure it is correct and then inform the referee.

"It's a big decision to change the decision of a referee on the field so there is a lot of pressure for the video referee. That is why I think it is important for the video referee to speak with the referee before the match and they both have a similar understanding. And that the video referee is operating at the same level as the referee so they are used to making decisions in these same types of matches."

What about the time factor?

"I think decisions will be made quicker with more experience, but first and foremost the footballing world wants correct decisions, so even if it takes a bit longer than would be expected the priority is to make the right decision.

"Similar to the referee on the pitch, if you rush into a decision and only maybe look at one angle you could possibly make the wrong decision and then there would be all sorts of problems. There is less of an understanding with the video referee of wrong decisions taking place and not being corrected.

"The time factor will improve as video referees gain more experience and the operators who are working with the referees become more used to what the referee is looking for. First and foremost at the moment, it's about getting the decision correct.

"It will take time. You can't just put someone into a van and ask them to be an excellent video referee. That is why so many countries are trialling the video referee offline for a season before they bring it into their domestic campaigns."

How much training did you get?

"We were really pleased with the training offered by FIFA because at the tournament every day the referees and the assistant referees trained on the field with the players and every day we were in the van training with the video operators and looking at the screens and making decisions.

"Obviously, these decisions are simulated at training, so you get the opportunity to make 20 or 30 decisions when in a tournament you might only make one, and in a season you might only make one or two. It was good for us to practise and get used to it and also work in the same team so we get used to each other and what to look for."

Did it work well?

"I think it has been successful. I can only speak from my experience in Korea where there were several incidents overturned.

"A decision I was involved in saw the assistant referee keep his flag down correctly because it says in the laws of the game that in a very tight offside situation the advantage should go to the attacking team. However, when we reviewed the incident it was possible to tell the officials on the field that the attacker was half a metre offside. This is factual. So we were able to correct the decision.

It will take time. You can't just put someone into a van and ask them to be an excellent video referee.

"The thing that amazed me about the decision was the fact there was zero dissent from the players. They accepted the decision in the van."

What tweaks need to be made?

"Practice is required. It's a matter of everybody getting used to working with the video referee. People think it's only about the video referee but the referees on the field have to be trained and operate very differently.

"For example, if there is a penalty claim in the match and the referee doesn't give it and the ball goes out for a corner or goal kick it's so important for the referee to delay the restart to allow the video referee to review the incident. If the game restarts it is not possible to go back if it was wrong. It's about everybody involved in it becoming more used to the protocol.

"Sometimes in the match it's good for the referee to allow the play to restart very quickly because people move on from a decision, but with the video referee if there is anything debatable it's crucial that the referee delays the restart."

Will it be used at the World Cup in Russia?

"FIFA have told us they are using these tournaments this year to get information and there are countries trialling it too. I am very wary of talking about the U20 World Cup and the Confederations Cup as experiments because teams in the competitions were looking for decisions to be correct. It has been trialled at these competitions and will be trialled more domestically and then in January or February FIFA will make a decision on the World Cup.

"What I really liked about the tournament in Korea was FIFA were very keen to ask everybody involved what their experience was."

What about using it in the Premier League?

"It's what football wants. Football is looking for anything that can provide the correct decisions. We need to get the balance right. Of course we always want the right decisions and if technology can help…but we need to remember that the referee will make the decisions on the field and ultimately even if the video referee tells the referee to make a decision then it's the referee who makes the final decisions always. I don't think we should detract from the referees on the field making decisions."

How does it differ to rugby or cricket?

"At first I was unsure it would work because of the stop-start nature but that's not really the case. Clear refereeing errors don't happen very often in matches. People can disagree over incidents but we are talking about factual decisions that are clear to be changed. It's very similar in other sports where they are looking for other decisions but it needs to be factual to be changed."

What do you think? Do you want to see VAR continue? What changes need to be made? Let us know in the comments section below or tweet @SkyFootball.