Why Yashasvi Jaiswals' dismissal has reignited questions about DRS in cricket | News explained

What happened at the MCG?

Jaiswal tickled (or gloved, or both) a short ball from Pat Cummins to wicketkeeper Alex Carey. The on-field referee ruled it was not over. Cummins asked for a review, but the Snicko didn't detect a nick.

Yet the third umpire overturned the decision because it appeared to him as if there had been a clear and obvious deflection (which is compelling evidence), from the sticker just below the handle of the bat, and a ricochet off the glove . The ball noticeably changed direction and the television referee went along with the evidence provided by his eyes.

Later, Indian captain Rohit Sharma said Jaiswal himself felt he had crossed the line, nipping a potential scandal in the bud.

Then why is there still a problem?

Ultimately, while the right decision was made, a flaw was exposed with the Snicko: it doesn't register a spike when there's a glancing shot, that is, when the ball slides off the bat, rather than from the edges.

There is rarely any noise in those fast recordings. It only shows ambient noise, Warren Brennan, whose company BBG Sports operates Snicko, told the Sydney Morning Herald.

Glance shots are not Snicko's forte, while it is for Hot Spot, Brennan said, referring to a technology that uses infrared imaging to detect contact between the ball and the bat or pad.

So if Snicko doesn't detect every edge and is therefore not 100% accurate, why is it used? A few other incidents also demonstrate Snicko's unreliability.

In the second innings of the Perth Test in November, KL Rahul was convinced he had not come to the keeper, and the on-field umpire agreed. But after DRS the decision was changed because the Snicko showed a spike.

Earlier that month, during the Mumbai Test against South Africa, there was an issue with Rishabh Pants' dismissal during India's failed fourth-innings chase. There was doubt as to whether the bat had hit the pad or grazed the edge, and the third umpire changed the not-out call from the on-field umpires.

The other question: if Hot Spot does indeed register such edges, why isn't it used as part of DRS?

How do Snicko and Hot Spot work and how are they different?

Invented by English computer scientist Alan Paskett, Snickometer works on the principle of an audio waveform pattern. It filters the ambient noise and amplifies the relevant signal, that is, the sound generated when the bat hits the ball, which has a certain frequency using a resonance filter and an oscilloscope, which record and filter the sound waves.

Hot Spot uses technology originally devised by French scientist Nicholas Bion for use by the military. It is based on thermal infrared images of where the ball has grazed the bat. The bat's thermal imaging cameras placed behind the bowler at both ends record heat signatures created when the ball hits the bat (or pad or body).

Then why isn't Hot Spot widely used?

For starters, it is much more expensive than Snicko and can cost up to $10,000 per day. Furthermore, the technology is still used for military purposes in certain countries, and its use in cricket is therefore limited.

But everything else aside, the technology is not completely fail-safe. In the early days, batsmen, especially the great VVS Laxman, foiled this by applying Vaseline to the outer edge of the bat. But he wouldn't have applied Vaseline to the inside edge, otherwise an inside edge on the pad would go unnoticed and it would be given out even if he had nicked the ball.

Brennan, who adapted the Hot Spot technology for cricket, claimed that batsmen used silicone tape to prevent edges from being recorded. Most bats had some form of protective coating. Strangely, this protective coating would only cover half of the bat's edge, he said in 2013, urging the ICC to ban all such coatings.

The allegations escalated during that year's Ashes series. The issues of accuracy and cost led several broadcasters, including Sky and SuperSports, to avoid Hot Spot.

Is the other tool, HawkEye, more accurate?

It is the key technology in the DRS setup. The ball-tracking method, a brainchild of British mathematician, AI scientist and cricket fan Paul Hawkins, has been largely flawless. But even then, HawkEye is not wrong or controversial.

Many cricketers, especially Virat Kohli and England captain Ben Stokes, want the umpires' call to be removed. Stokes was left fuming after a series of lbw decisions went against his side's referee call during England's tour of India last year.

Stokes mentioned Joe Root's lbw dismissal in England's second innings in the fourth Test at Ranchi in February 2024. To the naked eye, Ravichandran's Ashwin ball also landed outside the leg stump, the umpire thought the same but at review, the footage showed the umpire landing the ball in line with the leg stick and hitting the stumps.

Earlier, in the third Test in Rajkot, Zak Crawley was given out by umpire Kumar Dharmasena, and the review upheld the decision. However, the images on TV showed that the ball missed the stumps. Match referee Jeff Crowe later admitted a glitch in the system, angering some of England's pundits who suspected footage manipulation.

Could the images have been manipulated?

It's highly unlikely. The technology company was not from the same country as the host broadcaster. HawkEye, which was criticized by English cricketers, comes from Great Britain.

To dispel such doubts, former England captain Michael Vaughan came up with a suggestion: put a camera and microphone in the truck so that while a decision is being made, we all know exactly what is going on and how many people are involved are involved. And when you put an ICC official in there too, we know that the integrity, which we talk about so much in the game, is intact, he said.