What is VAR and how will it be used for Brighton vs. Crystal Palace and Chelsea vs. Arsenal?

It’s never going to be “100 per cent perfect”, comes the strong endorsement of the Video Assistant Referee (VAR) technology from PGMOL chief Mike Riley ahead of Monday night’s English debut for the system that’s already seen use in other leagues — with incidents both proving its usefulness as well as its fallibility. After all, it’s still just a human being behind the video monitor who’s making the decisions.

So if there is a potentially “game-changing incident” in tonight’s Brighton vs. Crystal Palace FA Cup third round match derby, referee Andre Marriner may be called upon (by VAR Neil Swarbrick) to review the incident in question on a pitch-side monitor set up between the two dugouts. That setup should be fun when managers like Jurgen Klopp decide to go on one of his rants at the same time. The managers (and the players, too) are supposed to be cautioned or even sent off if they start interfering, but given how inconsistently such things are enforced, I’m not holding my breath. So maybe they’ll rethink the location later on. This is still just a trial of course.

In addition to tonight’s competitive debut for the technology in England, VAR will be deployed for both legs of the Chelsea vs. Arsenal League Cup semifinal and the final as well — but not the other semifinal, which is a bit of a strange decision even considering that it’s just a trial period. Let’s hope no game-changing incidents are missed in that one! (The official reasoning appears to be that Bristol City’s stadium does not have enough camera positions — and/or “can’t get the footage back to the league’s TV HQ” — but surely the key part of the system is the ability to rewind and review the footage, not the availability of extra footage. Also, the extra referees could sit in a truck outside the ground with all the rest of the TV trucks instead. But I digress.)

The Times has some relevant stats (though lacking overall context) from the first half of the current Serie A season:

• 45 corrections of initial decisions (1 every 4.2 matches)
• 18 penalties awarded
• 7 penalty calls overturned
• 9 goals ruled out for missed offsides callsthe l
• 3 goals allowed to stand after mistaken offsides calls

So, what is the big bad Vee Ayy Arr, and should we be concerned that now two referees will be in charge of a match? If the probability of the match referee alone being right is 96%, and the probability of the calls being right with the system is 98% (these are Riley’s generous numbers; feel free to guffaw loudly), the video referee would have to add 102% correct calls into the equation. Oops.

It’s a fairly simple implementation, just as it’s been used in the Netherlands, Italy, international friendlies, the Club World Cup, and elsewhere. In this setup, it can be used in four and only four “match-changing” cases (though some of the cases are pretty broad, like the potential red card offense cases, which still require judgement calls).

1. goals
2. red cards
3. penalties
4. mistaken identity (i.e. Gibbs / Oxlade-Chamberlain, right, Andre Marriner?)

The video referee (who is not at the match) is constantly monitoring the on-pitch referee, and can call a “factual” mistake or a subjective review down. In the case of the former, the on-pitch referee can then relay the correct decision (e.g. goal was offside) and restart play. In the case of the latter he has to go and review the play in question on the monitor. In either case, it shouldn’t take more than a couple minutes and the final decision rests with the on-pitch referee. As in all other instant replay and video review systems, there is language here that specifies that to overturn any call, there must be clear and obvious evidence.

And that’s it. The on-pitch referee will make that silly “don’t be a square, man” hand-signal, run to the review monitor, and make the perfect call.

And they all lived happily ever after.

Photo by Shaun Botterill - FIFA/FIFA via Getty Images