FIFA World Cup 2018: All you need to know about VAR

Video Assistant Referee (VAR) - FIFA World Cup 2018

The Video Assistant Referee (VAR) is a video assistance technology that is used to arrive at more accurate decisions and remove ambiguities when necessary, during the match.

The latest technological advancement in football involves a professional referee along with an assistant closely monitoring the game.

While video assistance was previously trialled in the FA Cup final and Carabao Cups as well as the German and Italian leagues, last season, it is the first time that FIFA has adopted such a technology.

"VAR will improve the accuracy of refereeing decisions from 96-98 percent," said Mike Riley, Managing Director of Professional Game Match Officials Limited (PGMOL).

What decisions can it take?

The VAR only intervenes when the on-field officials make a 'clear and obvious error' in one of the four key areas: Goals, Penalties, Red Cards and  mistaken identity.

Goals: While offside decisions are the most common reason for referring to VAR, it can intervene in other cases of infringement such as shirt pulling.

Penalties: Arguably the most problematic aspect of the game. VAR can also award or revoke penalties if there is a 'clear and obvious error' in the original decision.

Red cards: Referees can refer dangerous tackles and cases of violent conduct to the VAR as witnessed in the June 25 stalemate between Portugal and Iran, where Cristiano Ronaldo was subjected to a red card review after swinging an arm at Morteza Pouraliganji off the ball, although he was only shown a yellow card by the match official Enrique Caceres.

Mistaken identity: The VAR can be used if the referee sends off the wrong player, such as the infamous incident where referee Roger East had sent off Wes Brown instead of John O'Shea during a 2015 Premier League match between Sunderland and Manchester United.

How does it work?

The VAR comes into play in the following two scenarios:

The video referee relays information to the on-field referee, who raises his hand to pause the match and inform players that a decision is being reviewed.

The play only begins once the video referee is satisfied that the final decision is correct.

The referee can also refer a decision to the VAR. In this instance, the referee makes a 'rectangle' gesture (replicating a TV a screen), similar to the 'Third-Umpire' sign used by Umpires in Cricket.

The decision will then be reviewed and the same signal is made if he wishes to change his decision.

Where are the referees and how do they communicate?

The VAR referees are usually in a remote location with access to various camera angles. They are in constant touch with the on-field official, through an earpiece.

FIFA has asked both — officials and assistants — to wear their full kit while on duty at the World Cup.

How has it been worked in the World Cup?

VAR has been one of the biggest talking points of the 2018 FIFA World Cup.

Morocco and Watford winger Nordin Amrabat was unhappy with the newly instated system after it awarded Spain the equaliser in their Group B finale, despite it being disallowed originally by the on-field referee.

Both South Korean goals against Germany were also referred to the VAR, especially Kim Young-Gwon's opener, which was initially ruled as an offside.