Scenario: Mitchell Starc has the ball in hand and is all set to uproot (Joe) Root who is playing the Aussies quite well so far. He takes few steps and then starts charging in, the ball in his hand like a boomerang, and then releases it like a trebuchet throwing a projectile. The ball hits the deck, swings in and hits the front pad of Joe Root. The whole Australian team goes up in arms, appealing as their life depends on it. The only problem, Kumar Dharmasena (the on-field umpire) isn’t interested in raising his finger. So after a few seconds of consultation with his keeper and bowler, Aaron Finch brings his arms together and forms a T sign, signaling to Dharmasena that he wants to review his not-out decision. Now whether the third umpire judges it out or not-out remains to be seen but the question is, just what exactly is Decision Review System, commonly known as by its initials DRS.
So what is Decision Review System (DRS)
Decision Review System (or Umpire Decision Review System) was introduced to give players the ability to challenge the decision of on-field umpires. The purpose was to reduce the howlers i.e. the decisions made by umpires which proved to be completely incorrect. Examples might be a batsman given LBW (leg before wicket) when there was an inside-edge, a caught-behind when the batsman hasn’t nicked the ball, etc.
When was DRS introduced?
The system was first introduced in 2008, during the India vs Sri Lanka test and was officially introduced later on by ICC during the Test between Pakistan and New Zealand in 2009. It got introduced in ODI cricket in 2011 while T20 internationals got the review system in 2017.
How can one signal for review?
If the fielding side challenges the not-out decision of the on-field umpire, the captain has to make a T sign which will indicate that on-field umpire should refer that decision to the third umpire for review. The procedure is also similar if the batsman feels that he has been judged out incorrectly by the on-field umpire. By making a T sign, he can indicate to the on-field umpire to refer the decision to the third umpire for further inspection.
Players have to decide within 15 seconds that they want to challenge the on-field decision. The time will start as soon as the umpire has made his initial decision.
How many reviews do teams get?
That depends on the format of the game. In test cricket, both teams get two reviews per innings while in one-day internationals and T20 cricket, both teams get one review each.
What are successful and unsuccessful reviews?
When the players are successful in overturning the on-field call, the review will be considered as successful. In that case, the team will retain its review. On the other hand, if the on-field decision was proven to be correct completely (i.e. the final result didn’t turn out to be umpire’s call which will be explained later ), the review will be considered as unsuccessful and the team will lose the review. In the case where the decision turns out to be umpire’s call, the review will be considered unsuccessful (in a sense that the player was unsuccessful in overturning the on-field decision) but the team will not lose a review.
How does the whole process work?
Now comes the technical nitty-gritty. The player review could be for either caught (nicked behind, an edge carried to a close-in fielder or any other instance like that) or LBW.
In Case of LBW
After the signal being made for a review, the umpire will refer the decision to the third umpire. The third umpire will use technological aids to judge whether the on-field decision was correct or not. First, there will be a check of no-ball and when that’s clear, the umpire will look for any edge by the batsman via the help of ultra-edge (or Snicko) and hot spot (both will be explained later), or either one of them depending what technological aid is available. If there appears to be no edge involved, the umpire will then proceed to ball tracking to judge where did the ball pitch, where was the impact on batsman pads, and whether the ball is hitting the wicket or not.
The ball pitched means where did the ball land on the pitch. As depicted in figure 1, if it landed on the leg side of the pitch, the case for an LBW is closed straight away. The ball has to land in the middle to the off-side region in order to bring LBW case into consideration.
Impact on batsman pads means that the ball has to strike the pad where the pad and the stumps are in parallel to one another. Otherwise, the case for an LBW would not be considered.
The final part is where ball tracking, based on multiple factors (such as angle of the delivery, landing of the ball, etc), would judge whether the ball would hit the stumps or not.
In Case of Caught
This can occur either as caught behind (batsman nicking to keeper or to slip fielder) or an edge carried to a close-in fielder. There might be other cases as well but these two are the most prevalent ones. In either case, the umpire will first check the no-ball. Afterward, via the help of ultra-edge (and hot spot if available), the third umpire will try to judge whether there is clear evidence of an edge or not.
Wait, what is Umpire’s call?
To successfully overturn the on-field umpire’s decision, there should be clear evidence that the umpire has made an incorrect decision. So umpire’s call is when there isn’t enough evidence to suggest that umpire has made an error in judgement. Examples would be only a marginal part of the ball hitting the stumps, or an edge but replays showing that bat was also hitting the ground or batsman’s pad at the same time while when the ball is being close to bat.
If the outcome of a review turns out to be umpire’s call, the side calling for a review does not lose a review.
Snicko? Is that a kind of snake?
No. Snicko or ultra edge consists of directional microphones which detect a sound (or a snick, hence the name Snicko) made when the ball hits the bat or pad.
And what is Hot Spot?
Hot Spot is an infrared imaging system which consists of two infrared cameras used to detect any possible nick by the batsman. After the ball comes in contact with batsman bat or any other accessory (such as the bat, glove or helmet), the image will show a bright mark which will then be used in decision making by the third umpire.
Also known as ball tracking, it is a visual tracking technology that plots the trajectory of the ball which it determines is the statistically most accurate one. It is used by the third umpire to determine whether the ball will hit the stumps or not after an LBW decision is being challenged, either by fielding side or by the batsman.
Has the system been successful in eradicating incorrect decisions?
To an extent, yes. However, the system has been criticized by some players and cricket experts due to technological aids not being faultless. Nevertheless, it has certainly helped in situations where on-field decisions were absolute shockers (for example, an LBW given when there was an inside edge) which is primarily been the purpose of it. Having said that, there is definitely room for improvement, most importantly in how the system should be used rather than about its technical flaws or limitations.