Umpire's Call explained: Why is that not out?

Cricket can be a complicated sport at times, even for those well-versed in the game. And especially so given the laws and playing conditions are regularly updated and some rules may be in play for one format but not for others.

When the Decision Review System (DRS) was introduced to international cricket 13 years ago in 2009, the phrase "umpire's call" quickly became part of the cricketing vernacular.

But many fans and commentators still don't understand how it works, or disagree with its existence entirely.  

In April, the head of the ICC's powerful and influential Cricket Committee, Anil Kumble, attempted to explain why the umpire's call was still seen as a vital aspect of DRS.

"The principle underpinning DRS was to correct clear errors in the game whilst ensuring the role of the umpire as the decision-maker on the field of play was preserved, bearing in mind the element of prediction involved with the technology," Kumble said. 

"Umpire's call allows that to happen, which is why it is important it remains." 

Given it's here to stay, let's take a closer look at how it works and the role it plays in DRS.

The three zones

When ball tracking technology is used to determine the outcome of a delivery, a three-step process decides the batter's fate. 

Firstly, there's the Pitching Zone. It's the two-dimensional shaded line that runs down the length of the pitch, with its boundaries set at the outer edge of the stumps at each end. 

Secondly, there is the Impact Zone, where the ball hits the pad (or bat, for some of the really bad reviews we've seen) for the first time. It is a three-dimensional space extending between both sets of stumps, from ground level to an indefinite height vertically. Its horizontal boundaries are the outer edge of leg and off stump. 

Finally, the Wicket Zone is a two-dimensional area bounded by the stumps, from their base to the top of the bails, and the full width from the outer edge of the off and leg stumps.

Understanding these fixed boundaries is fundamental to correctly understanding how DRS works for lbw reviews. But of course things are never so black and white, and when impact in any of these zones straddle the boundaries of the zones, confusion often arises.

Pitching outside? Broad v Carey

Alex Carey was able to overturn this decision in the Hobart Ashes Test thanks to one of the intricacies of the review system.

Just over half of the ball pitched outside the line of leg stump, meaning Carey should be not out under the lbw law. 

However, one thing to note is that there is no umpire's call for where the ball pitches. 

For both the second and third steps in the system, impact and wickets, if between one per cent and 50 per cent of the ball is in the zone and half the ball is out, the decision defers back to the umpire's original decision. 

But not for the pitching of the ball. The ICC declined to comment on why this is the case, however it is the only stage of the process where ball tracking can say with a high degree of certainty exactly where the ball has landed, and therefore no predictions need to be made. 

In the Carey-Broad example, Carey reviewed and managed to overturn the umpire's out decision. However, if the batter was given not out and the bowling side were to review this decision, somewhat harshly they would lose that review. 

But what would happen if the ball was exactly 50 per cent in and 50 per cent out of the pitching zone? 

According to the ICC, the ball must be more than 50 per cent out to be considered outside the line, so in this example, the decision would rule in the bowler's favour. 

Too far down? Lyon v Sohail

Umpire's call will come into play when the impact is a long way from the stumps.

The playing conditions stipulate that if the first point of interception was 300cm or more from the stumps, then the umpire's call remains.

In this, as the batter gets further from the stumps, the margin of error in the system that predicts the ball's paths increases. There is only so much information that can be gathered from a couple of cameras 100m away. 

So while Nathan Lyon's to delivery to Haris Sohail is hitting the stumps according to the ball tracking, the benefit of the doubt goes to the umpire - and their original judgement overrules the judgement of the technology.

Here's an example where Aaron Finch comes down the wicket to Maheesh Theekshana with a handy visualisation showing distance from the stumps.

In this scenario, the ball struck Finch's pad 290cm from the stumps so the impact point brought up a red light. If Finch was 10cm or more further down the wicket, the impact point would have been umpire's call.  

This rule also comes into play if the batter is more than 250cm or more from the stumps and the distance between the ball pitching and striking the batter is 40cm or less. 

So if a batter is outside the crease and the ball 'half-volleys' into their pad, like in the Anderson example above, the decision is going to stay with the umpire as there isn't enough information for ball tracking to predict where the ball is going to go. 

Is it hitting the stumps? Ashwin v Starc

The wickets zone has long been a bone of contention for the system and it has been tweaked on several occasions in the DRS's short history. 

As it stands today (March 2022), the wickets zone spans from the base of the stumps, to the outside of the outer stumps, to the top of the stumps.

Confusingly, 'top of the stumps' here includes the bails. Before April 2021, the wickets zone only extended to the bottom of the bails, meaning that deliveries that were clipping the bails would remain umpire's call, like this Mitchell Starc decision off the bowling of Ravichandran Ashwin from December 2020. 

If that same delivery was reviewed from 2022 onwards, Starc would see three reds and Ashwin would have his wicket.