VAR, What is it Good For?
Introduction
As Edwin Starr famously said, VAR, what is it good for? Well, let's find out...
Player Speed
To get an idea of what VAR can and can't do we need to know how fast the players are moving on the pitch. According to this article in The Express and this one by Sky Sports, it's not uncommon for players to be able to reach speeds of 33km/hour upwards.
What About the VAR Cameras?
VAR has access to the broadcast footage of the match so the exact resolution of the cameras will vary depending on the broadcaster but in the case of Sky Sports and BT here in the UK they record at a resolution of 50 frames per second
What Does This Mean?
- 50 frames per second means an image is captured by the camera every 0.02 seconds
- A footballer running at 33km/h is moving 18cm every 0.02 seconds
- Therefore, a footballer can potentially move 18cm between two frames being captured
Now imagine VAR is assessing an offside decision by looking at the earliest frame where the ball was clearly played forwards. Chances are the ball was not played exactly at that moment the frame was captured and actually occurred at some point between the current frame and the previous one 0.02 seconds ago. Since we know that players can move 18cm between frames the frame being viewed by VAR is potentially out by up to 18cm.
It gets worse than this though as we haven't accounted for the defender moving. As a worst case scenario the defender could be sprinting in the opposite direction to the attacker, whilst trying to play the offside trap for example.
This means the image being viewed by VAR to determine whether a player is offside or not has potentially occurred late enough after the ball has been played for the defender and attacker to have moved apart by 36cm.
Therefore if the attacking player is shown to be offside by 36cm or less then VAR has no absolutely no idea whether they were really offside at the time the ball was actually played. This is a fairly hefty margin of error, which effectively renders VAR unsuitable for any close offside decisions, particularly those where a player has an arm offside.
VAR making a decision it doesn't have the accuracy to do
Conclusions
VAR, what is it good for? Certainly not offside decisions!
Addendum
Apparently, in some situations VAR has access to super slow motion footage recorded at 120 frames per second. This reduces the potential error to around 15cm, which is still to large for those close offside calls.