By Terry O’Neill.

West Indian quick ,Joel Garner, calls it a “gimmick”. Former umpire Dickie Bird believes it undermines the authority of the onfield umpire. Pakistan spinner Saeed Ajmal thinks that it exaggerates the ball deviation while the Indian Cricket Board suggests that it is not accurate.

They are referring to the UDRS or the Umpires Decision Review System which came under intense scrutiny after the antics of Nigel Llong in the Adelaide test between Australia and New Zealand a  fortnight ago when he allowed  Australian batsman Nathan Lyon to continue batting after being obviously caught behind.

Former Australian captain Ian Chappell believes that the captains referrals need modernising as well.

“Instead of limiting the number of referrals and leaving them in the hands of the players, the use of referrals should be at the discretion of the umpires.”

The ICC showed some teeth finally when ,after the game, it announced that Llong’s decision had been wrong. But too little too late for New Zealand.

The  UDRS was first tested in an India/Sri Lankla match in 2008 and was officially introduced on 24^th November, 2009 at the Back Caps/Pakistan test at the University Oval in Dunedin.It was first used in an ODI in January 2011 on England’s tour of Australia. Initially its use was mandatory, but later optional if both teams agreed.

There are three components in the UDRS,Hawkeye, Eagle Eye and Virtual Eye.The Virtual Eye technology plots the trajectory of the bowled ball, that has been interrupted by  the batsman often by the pad and can determine whether the ball would have hit the wicket or not.

The Hot Spot is an infra- red imaging system that illustrates where the ball has been in contact with the bat or the pad. The Snickometer relies on directional microphones to detect small sounds made as the ball hits the bat or pad.It has a success rate of 90-95%.

A fielding team may use the system to dispute a “not out” decision. A batting team can dispute an “out” decision.On field umpires can ask the third umpire for certain close calls(run outs/stumpings), boundary calls and close catch calls.

Under the UDRS only incorrect decisions are reversed. The analysis of the third umpire is within established margins of error or if it is inconclusive the field umpires original decision stands.

When an lbw decision is evaluated and if the the replay demonstrates that the ball has made an impact more than 2.5 metres away from the wickets and travels less than 40 cm before hitting the batsman then any not out decision given by the field umpire stands.

The only time an lbw decision will be reversed in favour of the bowler is if the batsman is 2.5-3.5 metres  away from the wicket and the ball travels more than 40cm after pitching before hitting the batsman.Some part of the ball must be hitting the middle stump and the whole ball must be hitting the wickets below the bails. If not the call stands. Sounds easy?