What is the Decision Review System (DRS) in Cricket?

Umpires are vital in ensuring a smooth and controversy-free cricket match, but their human fallibility often leaves scope for errors. The Decision Review System (DRS) is utilized to prevent such errors from negatively impacting the game.

DRS in cricket is a technology-based system that helps players to request reviews of the on-field decisions made by umpires. 

On-field batters or fielding teams can use DRS for LBW or caught mode of dismissals if they feel they have been unfairly dismissed due to a wrong call. However, only ‘out’ or ‘not out’ decisions can be reviewed in international cricket unlike the Indian Premier League, where players can also review wide balls. The DRS can also assist on-field umpires in determining on an inconclusive catch or a runout. In such cases, the third umpire helps in making a decision.

History of DRS

Since its inception in 2008, the DRS has significantly transformed cricket. It was first used in 2008 during the India vs Sri Lanka Test match in Colombo. Virender Sehwag, an Indian opener, became the first batter to be dismissed under the DRS system. Back then, it was called the Umpire Decision Review System (UDRS).

While Test cricket got the first taste of the DRS in 2008, the system was incorporated into ODI in 2011. The DRS was introduced in T20Is in 2017. 

The DRS has made significant progress, with even domestic T20 leagues worldwide utilizing the review system to ensure fair play.

Types of DRS

A DRS is of two types: a player review or an umpire review.

The on-field umpires possess the authority to refer certain decisions to the third umpire, such as run-outs, stumpings, bowled, hit wickets, fair catches, bump balls or boundary checks. This referral occurs when the on-field umpire signals by making a TV screen shape with their hands. This is an ‘umpire review’ and the number of umpire reviews that can be taken in a match is not restricted.

On the other hand, player DRS is a request to review an on-field umpire's decision regarding a dismissal, except for 'timed out' cases. Teams cannot conduct a player review if they have already exhausted the maximum number of unsuccessful reviews.

A player review is only applicable to specific decisions related to the caught or LBW. A player requests a review by making a 'T' sign with both forearms at head height within 15 seconds after the ball is bowled. The DRS timer starts the moment a ball has been completed i.e. when it’s not in play anymore.

The captain of the fielding team initiates a player review for a 'not out' decision, while the batter involved in the dismissal can request a review for an 'out' decision. This process is not allowed to receive any external input from sources like the dressing room.

Upon a valid player review request, the on-field umpire communicates this to the third umpire using a TV screen gesture. The consultation involves two-way radio communication between the third umpire and on-field umpires to exchange information about the appeal, decision, and relevant details.

During the consultation, if the third umpire cannot definitively reverse or uphold the original decision due to inconclusive evidence during consultation, the on-field umpire's call remains. If the initial call is reversed, the on-field umpire indicates the reversal before confirming the outcome.

Tools in DRS

The Decision Review System utilizes advanced technology to guarantee fairness in sports. The DRS employs advanced technology for ball-tracking, ultra-motion cameras, sound sensors, and thermal imaging.

In instances like LBW reviews, sophisticated ball-tracking technologies like Hawk Eye or Virtual Eye are utilized. These systems analyze the ball's trajectory and pitching point of the ball to determine whether it would have hit the stumps, despite the batter's position.

Devices like the Snickometer or Ultraedge are used in contentious LBW or caught-behind appeals. Equipped with highly sensitive sensors, they detect minute sounds generated when the ball interacts with the bat, pad or the batter. The third umpire uses ultra-motion cameras to accurately interpret data, ensuring any audio spike aligns before, during, or after the ball's bat passage.

Hot Spot, unlike other tools, operates on a different premise but shares the objective of confirming the ball's contact. The innovative system uses Infrared imaging to verify if the ball made contact with the bat, pad, or any part of the batter.

Cover Credits - BCCI Official