In cricket, in UDRS screen, if the ball hits the wicket, then why is not out still given?
I saw this situation so many times happened; bowler appealed for UDRS for LBW, in UDRS it shows ball hits the wicket, but still not out is given sometimes.
The general principle is that an umpire's LBW decision is overruled only if there is "conclusive" evidence from the UDRS that the decision was wrong; if the UDRS presents only marginal evidence, then the original decision stands - this is known as "Umpire's Call". The specifics vary according to the exact type of cricket being played and are amended occasionally - you'd need to read the exact playing conditions for the match you're interested in.
Quoting from the current Test Match playing conditions, Appendix 2, section 3.3(iii):
iii) With regard to determining whether the ball was likely to have hit the stumps:
If a ‘not out’ decision is being reviewed, in order to report that the ball is hitting the stumps, the evidence provided by technology should show that the centre of the ball would have hit the stumps within an area demarcated by a line drawn below the lower edge of the bails and down the middle of the outer stumps.
However, where the evidence shows that the ball would have hit the stumps within the demarcated area as set out above but that:
- The point of impact is 300cm or more from the stumps; or
- The point of impact is more than 250cm but less than 300cm from the stumps and the distance between point of pitching and point of impact is less than 40cm, the original decision will stand (i.e. not out).
- If an ‘out’ decision is being reviewed, in order to report that the ball is missing the stumps, the evidence of the technology should show that no part of the ball would have made contact with any part of the stumps or bails.