You can almost model it mathematically.
Refs are inconsistent. Always have been, always will be, because many decisions are subjective.
Adding a second ref multiplies this inconsistency
So, if you consider a decision, say a pen that isn’t an obvious ‘clean him out’ pen-
The ref can see it as a pen or not.
The VAR ref may have a different view but then has to decide if his view is different enough to actually overturn the ref’s initial decision. Different VAR refs will take slightly different approaches to this.
Effectively you get Inconsistency x Inconsistency = Inconsistency Squared.
Because of this, VAR will not work until the ref is allowed to review his decision on the pitch side screen.
I also like that because it puts the referee back in charge of his decisions, something that isn't happening currently. It was rejected initially because it was said it would take too much time out of the game. But it can't take more time out of the game than the current arrangement, where 30,000 + fans and 22 football players stand around twiddling their thumbs, wondering what decision the mysteriously absent official, with a view on the game that no one else has, will come to.
However, I still think VAR is unnecessary. At its essence, this is about a game of "sport" and never in the history of the game of football has it been about measuring offside decisions in millimetres, for example. Always, in the history of the game, offside decisions have been somewhat controversial. They've changed the laws regarding offside to try and improve it, but at the end of the day it comes down to a subjective, judgemental call, from the referee. The linesmen are positioned thus in order to have the best view to call the offside, so the conversation between referee and linesman ought to give a pretty accurate view, not in terms of millimetres, but in terms of whether the player has gained an unfair and advantageous positioning. And that's what it should be about - it's about playing within the spirit of the rules, not measuring by how many millimetres a player stayed within the rules. I think we've lost sight of that, and VAR, regrettably, has some other unwanted side-effects. It makes fans feel removed and alienated from what is happening on the pitch and it kills spontaneity.
I drew a comparison with American Football, when I posted my concerns about VAR, before the season started. I said that I think it will be the thin end of the wedge and we will end up with a game which is being stopped frequently for decisions to be analysed - and it will kill the game.
It's happening and the fans, the players, the managers, are all seemingly powerless to stop it. VAR is here to stay. It doesn't matter whether the supporter going through the turnstile like it - the most important customers are the armchair millions watching across the globe - and obviously it's for them, because it provides a bit of drama and allows sufficient time during the examination of incidents, to pop out and make a cup of tea.