Video Assistant Referee causes controversy every week in the Premier League and the FA Cup, but how are decisions made, and are they correct?

After each weekend we take a look at the major incidents, to examine and explain the process both in terms of VAR protocol and the Laws of the Game.

- How VAR decisions have affected every Prem club in 2023-24
- VAR in the Premier League: Ultimate guide

In this week's VAR Review: Should Nélson Semedo have been sent off for Wolves? Why did it take so long to disallow West Ham United's "winner" against Aston Villa? And how do referees judge red cards in the penalty area, and possible handball?

Wolves 2-1 Coventry

Possible red card: Semedo challenge on O'Hare

What happened: Wolves were on the attack with a corner in the 74th minute in this FA Cup quarterfinal tie. The Coventry defence cleared their lines and Callum O'Hare looked to start a break. Nélson Semedo tried to nick the ball off the Coventry City player, with O'Hare going down holding his head. Referee Sam Barrott gave no free kick and allowed play to continue. The VAR checked the incident for a possible red card.

VAR decision: No red card.

VAR review: If Barrott thought there was no contact by Semedo, this should have been a free kick to Coventry for playing in a dangerous manner and a yellow card for challenging in a way which could cause injury to an opponent.

And that's at the very least as Semedo did make contact with O'Hare, who needed treatment and appeared to have a mark on his nose. It should have been a red card through a VAR review. The height of the boot, that the opponent wasn't ducking into the ball and the speed of the Wolverhampton Wanderers player had to be dangerous.

Semedo somehow escaped because the VAR, Graham Scott, deemed it was reckless, not dangerous, with the small amount of contact a factor. If this was in the Premier League, the Independent Panel would likely rule it to be a missed red card.

We can compare it to the challenge by Diogo Jota on Tottenham Hotspur midfielder Oliver Skipp last season, with the Liverpool player booked for a high boot which made contact with the head. The Independent Panel supported the yellow card in that instance, as while Jota's raised boot could be considered dangerous it was in a standing position with no force, so a caution would be supportable. That wasn't the case with Semedo.

The Semedo incident still presents the question of when exactly a high boot warrants intervention. Last weekend, Liverpool wanted a late penalty against Manchester City when Jérémy Doku's boot made contact with the chest of Alexis Mac Allister; referee Michael Oliver decided there should be no spot kick. Doku's contact on Mac Allister was much lower and had no force; the Semedo and Jota incidents are much clearer examples of offences -- though Semedo didn't even concede an indirect free kick.

The VAR on the Liverpool match was Stuart Attwell, and Attwell was in the VAR hub for this game alongside Scott.

The Football Association, which controls referee appointments in its own competition, has added a support VAR this season. Just as FIFA and UEFA do for major games, this is a second referee providing help and advice. For this game it was Attwell, alongside the assistant VAR, Natalie Aspinall.

Possible handball: Simms when scoring

What happened: Coventry City took the lead in the 52nd minute when Joel Latibeaudiere headed the ball across the six-yard box on a free-kick routine, with Ellis Simms bundling home from close range. However, there was a question of whether the ball went in off Simms' arm.

VAR decision: Goal stands.

VAR review: This was the first of three similar situations over the weekend. It's not about a clear and obvious error, it's a factual decision for the VAR who must believe they have conclusive proof that the ball has hit the arm.

If the ball touches the goal scorer's arm, then the goal has to be disallowed. It doesn't matter if there was a deflection, or if the scorer was under pressure, or that the arm was close to the body.

It wasn't clear whether the ball had touched the arm at all, or if had only bounced up only off the chest, or perhaps most importantly if it was too high on the arm to be considered a handball offence.

There's every chance the ball did hit the arm. But the VAR needs to be absolutely certain to overturn the on-field decision of goal. It was fair for the VAR to leave this to the on-field decision.

These checks seem to take a long time because it can be difficult to pinpoint where the ball has hit the body, even with multiple synced cameras which the VAR has at their disposal.

The VAR did get involved at West Ham United on Sunday to disallow Michail Antonio's 48th-minute effort which would have put them two goals up against Aston Villa. This again took a while, with the VAR deciding the ball came off the striker's arm as he had it tucked into his body.

Luton Town also had a goal chalked off for accidental handball before a goal in their 1-1 draw at home to Nottingham Forest. This one was spotted on the field by referee Darren England, so it was a rare case of the VAR having to find clear evidence that the ball hadn't touched the arm of the goal scorer, Teden Mengi.

It doesn't mean the VAR always gets this right, of course. The Premier League's Key Match Incidents Panel ruled that Jordan Ayew's goal for Crystal Palace against Tottenham should have been disallowed. The VAR on the Palace game? Once again it was Attwell.

West Ham 1-1 Aston Villa

Possible penalty: Handball by Emerson

What happened: Aston Villa were on the attack in the 23rd minute when Leon Bailey broke into the area and tried to lift a pass to Ezri Konsa. The ball hit the arm of West Ham United defender Emerson, with referee Jarred Gillett waving away claims for a penalty.

VAR decision: No penalty.

VAR review: Emerson is fortunate, because if the referee had awarded a penalty it wouldn't have been overturned.

The West Ham player had his arm away from his body and was pointing to give directions to a teammate, and while he did try to withdraw his arm there's still an argument that it has blocked the forward pass to Konsa.

You could also argue that Emerson had his arm in an expected position for his action, pointing for a teammate, but it's a close call and it's almost certainly given in the other top European leagues.

Possible handball: Soucek before Bowen goal

What happened: West Ham scored a dramatic, 96th-minute winner when Tomás Soucek tried to force the ball over the line, and it went into the goal off Jarrod Bowen's head. But was there a handball, an offside or a foul in amongst it all? The VAR checked.

VAR decision: Goal disallowed for deliberate handball by Soucek.

VAR review: "The reviews are taking too long and it's affecting the flow of the game," Tony Scholes, the Premier League's chief football officer, said in January. "It's to a degree understandable, given the level of scrutiny these guys are under. We're extremely aware of that and the need to improve that speed whilst always maintaining the accuracy."

This was the perfect case study, with a correct decision taking far too long.

It took five minutes and 20 seconds from the ball crossing the line to Gillett signalling that the goal had been disallowed. While it was a complicated review, no doubt learnings can be taken over how long the VAR spent on possible factual handballs rather than two obvious subjective offences. In trying to avoid the referee going to the pitchside monitor the VAR, Tony Harrington, made the whole review take far longer than necessary. Gillett ended up going to the screen anyway, so the process was a hindrance rather than a help.

The VAR had to check for a possible offside offence against Bowen when the ball was first played forward, and it got complicated after that.

It was credited to Soucek, yet in fact it was a Bowen goal that was disallowed. Soucek helped the ball on, it touched Bowen and then went in -- and this cause part of the delay.

Once the VAR noticed the ball had touched Bowen, where did it him him? If it was his face, a goal was possible. If it touched Bowen's arm, then it had to be ruled out. It was deemed there wasn't sufficient evidence that it was handball by Bowen.

So, no offence by Bowen, but what about Soucek? He helped the ball on with his arm but was it accidental? If so, it would be a goal as Soucek wasn't the goal scorer. If it was deliberate, the goal had to be disallowed. There looks to be a clear movement to ball with his right arm, which pushed it towards goal; Gillett was sent to the monitor to make the subjective decision.

The VAR team took so long checking the factual elements, yet the subjective handball was clear by Soucek. This could have been done so much quicker.

If it had been determined that the handball was accidental, there was also a possible foul by Soucek on Konsa which would have been taken into consideration.

Chelsea 4-2 Leicester

Possible penalty overturn and red card: Doyle challenge on Jackson

What happened: Nicolas Jackson broke through on goal in the 71st minute and was brought down by Callum Doyle on the edge of the area. Referee Andy Madley pointed to the spot, with the Leicester City player booked for the challenge. The VAR, Darren England, needed to check the award of the foul, and also the position where it took place.

VAR decision: Penalty changed to a free kick with the foul outside the area; Doyle yellow card upgraded to red.

VAR review: It's a VAR situation we've not seen in English football before, with a yellow card changed to red because a foul took place outside the area.

This is all about the double jeopardy exemption around denying an obvious goal-scoring opportunity, which says a player should only be booked if they give away a penalty and they were making a genuine attempt to play for the ball or to challenge an opponent.

Madley deemed the foul to be just inside the area, so produced the yellow card for Doyle under that exemption. There's an argument that Doyle, who clipped the right foot of Jackson causing him to trip over his own heels, should have been sent off but double jeopardy was widened last summer; any challenge with the feet is now unlikely to lead to a red card, unless it's reckless or a cynical attempt to take down an opponent. Something like this isn't given as a red card, there's a really high threshold.

As soon as it's identified that the foul is outside the area, Doyle loses that double jeopardy exemption as Chelsea don't get the penalty, and the caution has to be upgraded. Madley didn't have to go to the monitor because the VAR intervention is purely factual on position, and the card change is due process.

Burnley 2-1 Brentford

Possible penalty and red card: Reguilón challenge on Vitinho

What happened: The game was only four minutes old when Vitinho went down in the box as Sergio Reguilón challenged him. Referee Darren Bond allowed play to continue, but shortly afterwards the VAR, Paul Tierney, told him to stop the game and go to the monitor.

VAR decision: Penalty, scored by Jacob Bruun Larsen; Reguilón sent off.

VAR review: It highlights the positives of a protocol change made by PGMOL in December, but also an unintended negative too.

When Crystal Palace were awarded a VAR penalty against Liverpool three months ago, the game continued for a 1 minutes as first the foul and then the attacking phase were checked. It was decided that letting the play continue for so long when an offence had been identified was unnecessary, so in future play should be stopped and the referee sent to the monitor while the buildup was checked.

When Bond stopped the game and went pitchside he had to wait for the VAR to complete the offside check on Vitinho, which was close and took a little time to complete. The referee isn't shown this part on the screen, which is why the holding image remained in place for so long before the replay of the foul was shown.

There's no perfect solution when the ball stays in play on a possible penalty. Indeed, there might be a case in the future whereby play is stopped and it then turns out there was an offside, so the pitchside review is cancelled.

It's a different to the Doyle challenge in Chelsea vs. Leicester; Reguilón bundled into the back of Vitinho as he was about to shoot which wouldn't come under the double jeopardy exemption. If Reguilón had brought the Brentford player down shoulder-to-shoulder it could be seen as challenging an opponent, so a yellow card, but going into the back of a player who is about to shoot is going to be a red card.

Possible penalty: Fofana challenge on Jorgensen

What happened: Brentford had a corner in the 53rd minute. As the ball came over Mathias Jorgensen went to ground under pressure from David Datro Fofana, which the VAR checked for a penalty.

VAR decision: No penalty.

VAR review: "There was a clear penalty," Brentford boss Thomas Frank said. "How the ref and the VAR can't see that, it's incredible. It's not my view, it's 100% a clear penalty, especially when they speak about how you can't hold or grapple players. It's murder in the box."

Yet the VAR has been very consistent on these situations throughout the season, with no intervention made when both players are committing holding offences. Indeed, there have been several recently not logged as errors -- including when Mathias Jensen was holding onto Diogo Jota last month, which Liverpool wanted as a spot kick.

It seems as though the simultaneous holding exemption has only encouraged more of it on set pieces, as it's always likely the attacking player will also be in contact with the defender. We're too far down the line this season to make a change and suddenly start awarded a raft of VAR penalties for it, but it feels as though defensive players are able to get away with a much more aggressive approach.

Man United 4-3 Liverpool

Possible disallowed goal: Foul by Gomez on Fernandes before Salah scored

What happened: Liverpool took the lead in first-half stoppage time. Joe Gomez won the ball off Bruno Fernandes close to the touchline, crossed into the area and eventually the ball dropped to Mohamed Salah to score. But was there a foul as Gomez took possession?

VAR decision: Goal stands.

VAR review: No prospect of a VAR intervention, with Gomez winning the ball with his right foot before crossing into the box.

Possible offside: Rashford in the buildup to Antony goal

What happened: Manchester United equalised through Antony in the 87th minute on a break, but Marcus Rashford appeared to be offside at the start of the move. Why didn't the flag go up for offside?

VAR decision: Goal stands.

VAR review: Rashford was in front of the Liverpool defence when the pass was played forward, but a player isn't offside by their position alone -- their role in the move is what decides an offence.

Even though Virgil van Dijk had to intercept the pass, which gave possession back to United, Rashford wasn't close enough to the Liverpool player to be deemed to have made an impact.

This is how the modern offside law is. Van Dijk probably doesn't make such a stretched interception if Rashford isn't behind him, but the Liverpool player cannot gamble that he's offside. In effect, United still benefitted from Rashford being offside because it caused Van Dijk to stretch out a leg, but it's not a clear offside offence.

Some parts of this article include information provided by the Premier League and PGMOL.