The Umpire Decision Review System (abbreviated as UDRS or DRS) is a technology-based system used in the sport of "cricket. The system was first introduced in "Test cricket, for the sole purpose of reviewing controversial decisions made by the on-field "umpires as to whether or not a "batsman/"batswoman had been dismissed. The system was first tested in an India v Sri Lanka match in 2008, and was officially launched by the "International Cricket Council (ICC) on 24 November 2009 during the first Test match between "New Zealand and "Pakistan at the "University Oval in "Dunedin. It was first used in "One Day Internationals (ODI) in January 2011, during "England's tour of Australia. The ICC initially made the UDRS mandatory in all international matches, but later made its use optional, so that the system would only be used if both teams agree. The ICC has agreed to continue to work on the technology and will try to incorporate its use into all ICC events.
In October 2012, the ICC made amendments on "lbw protocols, increasing the margin of uncertainty when the ball hits the batsman/batswoman's pad. In July 2016, the rules were amended once again, reducing the margin of uncertainty. The updated rules were first used in the ODI match between "Ireland and South Africa in September 2016.
In September 2013, the ICC announced that for a trial period starting in October 2013, a team's referrals would be reset to two after 80 overs in an innings in Test matches. Previously each team had a maximum of two unsuccessful reviews in an innings.
In February 2017 the ICC agreed the use for all future "ICC World Twenty20 tournaments, with one review per team. The first T20 tournament scheduled to use the technology will be the "2018 ICC Women's World Twenty20. It was used in Knockout stages of "Pakistan Super League 2017 It was the first time DRS used in a T20 league.
Each team may make no more than two unsuccessful review requests per 80 overs during a Test match, and no more than one unsuccessful review request per innings during a One Day International. A fielding team may use the system to dispute a "not out" decision and a batting team may use it to dispute an "out" decision. The fielding team captain or the batsman/batswoman being dismissed invokes the challenge by signalling a "T" with the arms. Once the challenge is invoked, acknowledged, and agreed, the Third Umpire reviews the play. Additionally, at their discretion, field umpires may request the Third Umpire to review certain close calls such as line calls (to determine "run outs and "stumpings), boundary calls (to see if a batsman/batswoman hit a four or a six), or for close catch calls where neither umpire is sure if a catch was made. A challenge is only used in situations that did or could result in a dismissal: for example, to determine if the ball is a legal catch (making contact with the batsman/batswoman 's bat or glove and not touching the ground before being held by a fielder) or if a delivery made the criteria for a "leg before wicket dismissal (hitting the ground in line or on the off side and hitting the batsman/batswoman in line with a path that would have hit the wicket). The Third Umpire then reports to the on-field umpire whether his analysis supports the original call, contradicts the call, or is inconclusive. The on-field umpire then makes the final decision: either re-signalling a call that is standing or revoking a call that is being reversed and then making the corrected signal. Each team can initiate referrals up to the limit on unsuccessful reviews.
Under the DRS rule, only clearly incorrect decisions are reversed; if the Third Umpire's analysis is within established margins of error or is otherwise inconclusive, the on-field umpire's original call stands.
In 2013, ICC tested a broadcaster-free replay system. Under the experiment, a non-match umpire sits in a separate room with a giant monitor and has discretion over which replays to see rather than relying on the broadcaster. The non-match umpire mirrors the role of the third umpire without having the duty of making adjudications. The system was first used in an Ashes Test (where "Nigel Llong performed the duties of non-match umpire) and was repeated in a Pakistan-Sri Lanka ODI.
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The Decision Review System has generally received positive response from players and coaches since its launch, however there have been some criticisms as well. West Indies legend "Joel Garner labelled the system a "gimmick". Another West Indian "Ramnaresh Sarwan said that he was not a supporter of the experimental referral system. Former umpire "Dickie Bird also criticised the system, saying it undermines the authority of on-field umpires. The "cricketing board of India has expressed a skeptical view on the adoption of the system if it is near perfect. Pakistani spinner "Saeed Ajmal expressed dissatisfaction over the Decision Review System after a semi-final of the "2011 Cricket World Cup against India. He said that DRS showed the line of the ball deviating more than it actually did. Hawk-Eye officials admitted in December 2014 that their review technology made an error in a decision to give Pakistan opener "Shan Masood out in the second Test against New Zealand in Dubai (17-21 November 2014). At a meeting held at the ICC office in Dubai two weeks later, Hawk-Eye is understood to have conceded to Pakistan captain "Misbah-ul-Haq and team manager "Moin Khan that the projection used by their technology for the "Leg before wicket decision was incorrect. Also, a challenge can only be made by the captain within a 15-second window from when an initial decision is made, but it can be lengthened if no clear decision is made, especially they are assumed not out if there is no reaction by the umpire.