Video Assistant Referee causes controversy every week in the Premier League, 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.
In this week's VAR Review: The lowdown on Manchester United's VAR penalty against Everton, plus Manchester City's disallowed goal against Liverpool. Also, we look at penalty claims for Burnley, Nottingham Forest and Tottenham Hotspur.
Possible penalty: Young foul on Martial
What happened: Anthony Martial moved into the area in the 52nd minute and went to ground as he shifted past Ashley Young. Referee John Brooks blew the whistle, but to caution the Manchester United forward for diving. The VAR, Chris Kavanagh, initiated a review for a penalty.
VAR decision: Penalty, scored by Marcus Rashford.
VAR review: Everton manager Sean Dyche was far from happy, but you'll struggle to find many outside of Goodison Park who agree with him. Yet the question of consistency comes up after a similar incident in Burnley's game against West Ham United resulted in no VAR intervention.
Brooks felt that Martial had simulated a foul from Young to try to win a penalty, but there was clear contact from Young. From Brooks' view it would have looked more like a dive, but the other angles available to the VAR showed the foul.
There are fine margins for overturning this as a "clear and obvious" decision. Did Young stop his challenge when he realised he wasn't going to get the ball? To an extent, but he had already put his leg into a position that could trip Martial. Compare it to the incorrect awarded penalty to Newcastle United at Wolverhampton Wanderers, when Hwang Hee-Chan pulled out of a tackle on Fabian Schär. Hwang had stopped the swing of his boot and Schar initiated minimal contact on the Wolves' player's calf; Martial held his running line and effectively accepted the challenge from Young.
Winning a penalty isn't the same as initiating contact, or simulation. An attacker doesn't have to get out of way of an opponent if they have made a challenge.
Yet if Martial gets a VAR penalty for this, then Luca Koleosho has to get one for Burnley, too. The aim of VAR has never been to ensure consistency of decision-making on the pitch -- with so many subjective calls and the clear and obvious ethos, that would be impossible -- but it should be the aim on interventions. It's not easy, as there are 20 Select Group 1 referees working as VARs, and each of them will have their own subjective opinion on an incident. Yet fans and players expect similar incidents to be treated in the same way.
Koleosho looked to move past Vladimír Coufal, with the West Ham defender dangling out a leg behind him. Koleosho went over, and after a VAR check by Craig Pawson, the decision of referee Sam Barrott was supported. Perhaps the movement of Coufal's foot wasn't as pronounced as Young's, but both should be VAR penalties.
The VAR decided that the camera angle of Barrott's view meant there was no clear and obvious error, yet you could make the same argument for Brooks.
Dyche's main gripe was the outcome effectively being predetermined before the referee gets to the pitchside monitor. It's not the first time he has complained about this, but the referee isn't going over to have another look, only to approve the overturn.
Once at the monitor, the referee does retain all options, so the VAR isn't in control of the decision. The referee could have opted to stick with his decision, or give the penalty to Manchester United -- or even rescind Martial's yellow card but not award a spot kick. Brooks could also have shown Young, who had already been booked, a second yellow card.
In Europe's major leagues, a referee will stick with his own decision around five times a season. It happened four times in the Premier League last term, but only once so far in this campaign (compared to two at this stage last season).
The monitor is supposed to create a safety net for errors made by the VAR. It's unrealistic to think that a VAR will never make an incorrect intervention, so the screen should give the referee an opportunity to prevent his decision being incorrectly changed.
Yet if the referee has a predetermined idea he's got something wrong, it's still not a foolproof system. This season there have been only two incorrect VAR overturns, compared to five after 12 rounds last season.
Indeed, the one rejected overturn this season was logged as a mistake, with the Independent Key Match Incidents Panel feeling Arsenal's penalty against Manchester United should have stood; it's a judgement which Howard Webb, PGMOL's chief refereeing officer, didn't agree with and he supported the overturn on the VAR show in September.
The monitor is important for the referee's own game management. Both the Bundesliga and the Premier League tried making decisions without the pitchside screen in VAR's early years, but it was a failure in both competitions. The referee was unable to explain why his decision had been changed, which causes anger and confusion among players and coaching staff. If a referee has seen the incident himself, he's able to explain it to the captains and any affected player. It's also felt that a referee making the final call gives him authority on the pitch.
Possible goal: No foul on Alisson by Akanji
What happened: Rúben Dias thought he had put Manchester City two goals in front in the 68th minute when he side-footed home a corner from Julián Álvarez. However, referee Chris Kavanagh disallowed the goal and awarded a free kick to Alisson for a foul by Manuel Akanji (watch here.)
VAR decision: No goal.
VAR review: Akanji has his hand on Alisson's arm as he jumps to claim the ball. The goalkeeper can't catch it cleanly, and it drops to Dias.
It's a soft foul, and one that the VAR might not have given if the referee had allowed the goal -- but it's not going to be overturned by the VAR.
Goalkeepers need to be allowed to challenge for the ball with their arms, so any interference given by the referee won't be seen as an error.
Arsenal fans wondered why this was given as a foul, yet Gabriel didn't get a free kick for the challenge by Joelinton before Anthony Gordon scored for Newcastle United -- but as already discussed, the VAR's job isn't to give consistency of decision-making within games. In both cases, the decision of the on-field referee was not judged to be a clear and obvious error. And of course, a goalkeeper is far more likely to win a free kick if there is contact on his arm when jumping to catch a ball.
Possible penalty: Handball by Konsa, foul by Carlos on Gil
What happened: In the seventh minute, Brennan Johnson tried to help the ball back across the area. Emiliano Martínez jumped to try to claim the ball but dropped it after colliding with teammate Ezri Konsa, while Bryan Gil went to ground after a challenge by Diego Carlos (watch here.)
VAR decision: No penalty.
VAR review: For the first few minutes the pitchside referee review area was down after the monitor crashed. It meant any decision on a subjective incident would have to be made solely by the VAR, who still had the match pictures.
Even though the ball did hit the arm of Konsa, it was dropped onto him by the goalkeeper after they collided with each other as they fell. There would be no handball offence for this.
There could be a stronger case for Carlos' challenge on Gil, yet it looked far worse in slow-motion than at full speed. The Aston Villa player appeared to be trying to hold his ground and guard his goalkeeper, while Gil's body position was lower so the primary reason Carlos' arm made contact with his opponent's head.
Possible offside: Watkins when scoring
VAR decision: Goal disallowed.
VAR review: This offside check took over three minutes, but it was far closer than it initially looked.
If the attacking and defensive offside lines are touching, then it's within the tolerance level and the benefit of the doubt is given to the striker. This is about as close as it gets for the lines not to be overlapping and Watkins was millimetres from the goal being allowed to stand. What at first looked like a poor decision from the assistant was a much tighter call.
It still took too long as VARs continue to take their time over offside decisions to guard against any errors, after the major mistake to disallow a Liverpool goal at Tottenham.
There was another long check on Pau Torres' equalising goal on the stroke of half-time, yet this was a clearer onside decision with a gap between the two lines.
Possible penalty: Hinshelwood foul on Hudson-Odoi
What happened: Murillo played a ball into the area in the 70th minute and Callum Hudson-Odoi appeared to be held back by Brighton & Hove Albion defender Jack Hinshelwood. Referee Anthony Taylor looked over to his assistant, but they decided there wasn't enough to award a penalty. However, the VAR, Graham Scott, began a review for a spot kick.
VAR decision: Penalty, scored by Morgan Gibbs-White.
VAR review: Just because two players may have been held doesn't mean they are both offences. Earlier in the second half, Brighton's João Pedro was held back by Chris Wood and a penalty was awarded, so for this reason Nottingham Forest were adamant they should have a spot kick too for the holding of Hudson-Odoi.
Holding is an assessment of impact upon an opponent, and not just the act itself. Wood has his arm around the chest of Pedro, just as Marc Cucurella did on Erling Haaland for the penalty Taylor awarded to Manchester City at Chelsea before the international break. It's not going to be overturned.
Would the VAR have advised a penalty for Hinshelwood's challenge if there hadn't been a similar one earlier in the game? Perhaps not. However, as we have discussed, the VAR's job isn't to provide consistency of decision-making by a referee, and there doesn't appear to be a clear act of holding by Hinshelwood.
The argument that if you give the first one you have to give the second only holds if they are identical incidents, and it would have been better had the VAR not intervened. If the independent panel comes to the same conclusion, it would be the fourth incorrect VAR decision to go against Brighton this season.
The penalty award effectively led to the straight red card for Lewis Dunk, after he used abusive language toward Taylor because of the VAR overturn. Brighton will now be without their captain through suspension for two matches, against Chelsea and Brentford.
Possible offside: Trossard when scoring
VAR decision: Goal disallowed.
VAR review: Last month, Arsenal were left frustrated when the VAR was unable to draw the line to determine whether Gordon was offside before scoring Newcastle's winner.
The front of the ball was fully visible when Gabriel Jesus nodded it on, and the whole of Trossard's body was in shot, so there was no issue for the VAR to draw the offside line on this incident. This wasn't the case with Gordon's goal.
The save by Flekken doesn't reset the offside phase.
Possible penalty overturn: Kudus foul on Koleosho
What happened: Burnley were awarded a penalty in the 47th minute when Koleosho was brought down by Mohammed Kudus. Referee Sam Barrott had no hesitation in pointing to the spot, but would there be an overturn?
VAR decision: Penalty stands, scored by Jay Rodríguez.
VAR review: It's a difficult one to spot at first from the replays, but Kudus stands on Koleosho's right boot as he moves across the area. The Burnley player goes down in a way that would be expected from this kind of contact when moving quickly.
The penalty Sheffield United won against Wolves may have similarities, yet George Baldock appeared to collapse before any contact. While the independent panel thought the Baldock spot kick should have been overturned by the VAR, that is unlikely to be the case with Koleosho.
Possible handball: Édouard when scoring
VAR decision: Goal disallowed.
VAR review: An easy overturn for the VAR, Rob Jones. The ball hit the hand of Édouard after it bounced back onto him off defender Tom Lockyer. An attacker cannot score a goal immediately after the ball touches his arm.
Some parts of this article include information provided by the Premier League and PGMOL.