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: Was William Saliba's red card for Arsenal the correct decision? And does that mean Chelsea's Tosin Adarabioyo should have been sent off? And why was Manchester City's winning goal against Wolverhampton Wanderers deemed to be onside? That and all the other high-profile incidents on a busy weekend for VAR.

Bournemouth 2-0 Arsenal

Possible red card: Saliba challenge on Evanilson

What happened: The match was in the 30th minute when Leandro Trossard tried to play a pass back toward his own defence. However, the Belgium international got it wrong and placed it into open space in his own half. Evanilson was ahead of the Arsenal back line, but couldn't be offside as the ball was played by Trossard. As the AFC Bournemouth striker moved to run to the ball, he was pulled down by William Saliba. Referee Rob Jones produced a yellow card but the VAR, Jarred Gillett, checked for a possible red card.

VAR decision: Red card.

VAR review: There are four factors that referees have to consider when judging if a player has denied an obvious goal-scoring opportunity (DOGSO) -- which is a red card:

- distance between the offence and the goal
- general direction of the play
- likelihood of keeping or gaining control of the ball
- location and number of defenders

It's an assessment balanced across the four elements -- though the further away from goal a foul takes place the greater the importance of the other three. For instance, there's a greater chance for another defender could cover if a foul takes place in a deep position.

It's about judging the probabilities, and when the likelihood of a shot on goal outweighs any doubts -- and a couple of factors get this to the threshold of DOGSO for the VAR.

Importantly, the ball from Trossard is coming to a quick stop, rather than continuing to run through to David Raya, and it has been played in the direction of the goal. There's a strong likelihood that Evanilson will gain control of the ball. Ben White isn't in close proximity to realistically be able to make a challenge, so the location of defenders doesn't help Saliba. Raya also isn't coming out of his goal (the VAR showed the referee that the goalkeeper was backtracking rather than coming forward), so Evanilson has a very high chance of a shot on goal.

The best way to assess the situation is to imagine the picture with Saliba removed, meaning Evanilson has a clear run.

Then on Sunday, right at the start of Liverpool's match at home to Chelsea, we saw a similar situation. Yet no two incidents are ever the same, each is individually assessed according to set criteria, be that DOGSO or, as we'll come back to shortly, offside.

The foul by Tosin Adarabioyo on Diogo Jota did also happen a long way from goal, close to the halfway line. If we consider that the Saliba challenge just met the threshold for a VAR review for DOGSO, there were two very important differences which mean Adarabioyo's yellow card was a justifiable outcome.

The pass forward meant the ball was spinning toward the right channel, rather then toward goal. Levi Colwill was also on the cover behind which places doubts about Jota gaining control, and as the Liverpool player would not have had a direct run on goal there's enough doubt.

Wolves 1-2 Man City

Possible goal: No Silva offside on Stones goal

What happened: The game was into the final seconds of stoppage time when Man City won a corner. Phil Foden delivered from the right, and John Stones headed home. As the players celebrated, referee Chris Kavanagh was deep in conversation with his assistant about a possible offside against Bernardo Silva in front of the goalkeeper. After 28 seconds, the on-field officials decided to disallow the goal. It was checked by the VAR, Stuart Attwell. (watch here)

VAR decision: Goal.

VAR review: This caused a lot of controversy, probably because it involved a match-winning goal for one of the Big Six against a so-called smaller team, yet in truth it was a very straightforward decision.

The goal was originally ruled out because Silva was in goalkeeper José Sá's line of vision, which is impacting an opponent from an offside position.

How and when an offside phase is created is critical to this. When Foden delivers the corner there is some contact between Silva and Sá, but no player can be offside from a corner. So, during the flight of the corner, Silva could only be penalised for a standard foul -- and there was never enough in the bump. Anything that happens before the point of Stones' header is therefore irrelevant; when Stones heads the ball, Silva is not committing an offside offence. Silva has moved to the side of Sa and crouched down.

It's a very simple VAR overturn and undoubtedly the correct decision.

You can understand the frustration of Wolves manager Gary O'Neil, who last season saw a stoppage-time equaliser against West Ham United ruled out for offside in similar circumstances: similar but, again, not the same. Max Kilman had headed home from a corner but the VAR said the goal should be disallowed because of Tawanda Chirewa's position.

Unlike in the Silva example, Chirewa was stood directly in front of Lukasz Fabianski. Being in the line of vision isn't solely about the goalkeeper being able to see the ball, but also about possible impact. A player stood up directly in front of a goalkeeper, as Chirewa was, is always likely to be penalised. Silva was not directly in front of Sa when Stones headed the ball.

More comparable is the VAR intervention to allow Leicester City's goal at Fulham at the start of the season. The on-field officials had wrongly disallowed a Wout Faes goal for offside against Jamie Vardy; the striker was in contact with goalkeeper Bernd Leno when a cross came over, but at the point of the Faes header had moved away and wasn't in the line of vision.

As with all subjective decisions, the referee has to go to the monitor to confirm the overturn.

Southampton 2-3 Leicester

Possible penalty and red card: Fraser challenge on Vardy

What happened: Leicester City were on the attack in the 73rd minute when Fatawu Issahaku saw a header saved by Aaron Ramsdale. With the Southampton goalkeeper on the ground, Jamie Vardy seemed certain to tap home the loose ball but Ryan Manning got there first to clear. Vardy immediately complained to referee Anthony Taylor that he had been held back by Ryan Fraser, and it was looked at by the VAR, Alex Chilowicz.

VAR decision: Red card and penalty, scored by Vardy.

VAR review: In last week's VAR Review we discussed how impact is usually the key consideration for a holding offence. Chilowicz determined that by holding onto Vardy's shirt, Fraser had clearly prevented Vardy from being able to tap the ball home -- meaning it's not only a penalty, but also red card for denying an obvious goal-scoring opportunity.

The problem is that moments earlier Southampton had their own claim for a penalty, which was checked and cleared. The VAR agreed with the referee that André Ayew's actions were of no consequence as Paul Onuachu wouldn't have been able to challenge goalkeeper Mads Hermansen, who caught the ball.

In many respects the Ayew incident was more blatant. He was clearly holding Onuachu as a corner was delivered, resulting in a "coat hanger effect" on his shirt. It's the kind of holding that often does result in a penalty, but oddly in this case there was no appeal by Onuachu or any Southampton player (not that it should influence a possible review.)

It's probably the full-speed replay that persuades the VAR to back the referee's judgement that there was no impact, but it looks and feels like a non-footballing action by Ayew -- the kind that saw Everton concede a penalty against Newcastle when James Tarkowski dragged down Sandro Tonali. It's not as blatant as that, but there was still no interest in trying to play the ball or challenge an opponent.

Fulham 1-3 Aston Villa

Possible penalty: Handball by Cash

What happened: Fulham were on the attack in the 24th minute. A cross was swung over from the right by Kenny Tete, Raúl Jiménez headed the ball down and it hit the arm of Matty Cash. Jiménez appealed for the penalty, but referee Darren England was unmoved.

VAR decision: Penalty, Andreas Pereira shot saved by Emiliano Martínez.

VAR review: Before this incident, the Premier League had seen 71 matches played without a single handball penalty. It gave the impression that handball would have to be very blatant to penalised, even more so for a VAR intervention. And it's for that reason that this spot kick seems on the harsh side, as the ball hit Cash from such close proximity.

The VAR, Paul Tierney, has to consider if that arm position is justifiable for the player's movement. What goes against Cash is his arm being fully extended away from the body, creating a barrier as Jiménez's header is aimed to find Emile Smith Rowe, and this is why it's unlikely to be seen as a wrong intervention.

Liverpool 2-1 Chelsea

Possible penalty overturn: Sánchez challenge on Jones

What happened: Liverpool were awarded their second penalty of the game in first-half stoppage time. Curtis Jones broke through in the area and appeared to be clattered by goalkeeper Robert Sánchez, and referee John Brooks pointed to the spot. Michael Oliver on VAR duty checked the decision.

VAR decision: Penalty cancelled.

VAR review: At first it looked like a certain penalty, with Jones spinning over after Sánchez had collided with him. However, once the replay from the opposite end of the pitch showed that Sánchez had played the ball rather than the man, a VAR intervention was always likely.

Winning the ball doesn't automatically mean a penalty can't be awarded; if a player's actions are deemed reckless in winning the ball it can still be a foul. Sánchez probably ran quite close to this, though the way Jones flipped over perhaps made it look a little worse.

Tottenham 4-1 West Ham

Possible penalty: Handball by Udogie

What happened: Mohammed Kudus wanted a penalty in the 62nd minute when his goal-bound shot was stopped on the line by Destiny Udogie. Referee Andy Madley ignored the appeals for handball.

VAR decision: No penalty.

VAR review: While the ball did hit the arm of Udogie, it was against his body and therefore not making him any bigger. If the ball is going to hit the body regardless of the arm position, then the only way there could be a handball is if it's deliberate.

Possible red card: Violent conduct by Kudus

What happened: The game was in the 86th minute when Kudus and Micky van de Ven got involved in an altercation, which resulted in both sets of players steaming in. After things settled down, referee Madley chose to book both players, and it was checked by the VAR, Chris Kavanagh.

VAR decision: Red card.

VAR review: Within the melee the referee had missed a hand into the face by Kudus, twice. Either could be seen as violent conduct, but the second on Pape Matar Sarr, which saw the West Ham United forward thrust his hand forward into the face, was definitely a red card.

A player can get away with a hand to an opponent's face if "the force used was negligible," which is probably why the referee was shown the Sarr push rather than Van de Ven.

Ipswich 0-2 Everton

Possible penalty overturn: Foul by McNeil on Clarke

What happened: Ipswich Town were awarded a penalty in the 26th minute when Jack Clarke danced through the area and went down under a challenge from Dwight McNeil. Referee Michael Oliver pointed to the spot but the VAR, Graham Scott, sent him to the monitor to reverse his decision.

VAR decision: Penalty cancelled.

VAR review: In the last round before the international break. Everton boss Sean Dyche was furious when his side weren't given a penalty when Dominic Calvert-Lewin kicked the leg of Newcastle United defender Dan Burn when in the act of shooting. After this incident, you can't say the two outcomes weren't consistent.

As noted in the VAR Review for the incident, had a penalty been awarded in the Everton-Newcastle game there was a strong chance of a VAR intervention to cancel the spot kick for a foul by Calvert-Lewin.

And that's exactly what happened here, play restarted with a free kick to Everton for a foul by Clarke.

As the Ipswich player tries to shoot, McNeil doesn't make an attempt to place his foot into the running line and doesn't cause a foul himself.

Newcastle 0-1 Brighton

Possible penalty: Handball by Veltman

What happened: The game was in the seventh minute when Lewis Hall tried to break into the area, and went down under a challenge from Joël Veltman. The Brighton & Hove Albion player went to ground too, and as he did so appear to drag the ball back with his arm as Hall got back to his feet. Referee Peter Bankes didn't feel there was a handball offence as Hall appealed. (watch here)

VAR decision: No penalty.

VAR review: One of the exemptions from a handball offence covers a player using his arm to support his body, but that's overridden if there's a deliberate handball. So the VAR, Tony Harrington, has to be certain that Veltman has pulled the ball back to prevent it running to Hall, rather than just placing his arm down when falling.

The main camera angle looks damning, but the one behind the goal suggests Veltman's arm landed on the ball, rather than a purposeful act to move it away from running into Hall's path.

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