UDRS : The 2.5 Meter rule

[gvenkat]

Cricket Web - World Cup 2011 HQ: UDRS : The 2.5 Meter rule

 

[vcs]

why is it not 2.4 or 2? Who decides this arbitrary number?

This is the problem expressed in as few words as possible. It's kind of farcical that Bell would have been given out if he was say, only 2.49 metres down the crease. Assuming that the reason they have set this arbitrary number is that they don't have faith in Hawkeye's accuracy, it only puts further doubt into the viewer's mind as to whether the technology is reliable.

 

[Jayzamann]

The 2.5m rule has been put into place because it is from that point onwards that the precision of the ball tracking technology begins to reduce.

India v England: MS Dhoni angered by UDRS ruling | Cricket News | ICC Cricket World Cup 2011 | ESPN Cricinfo

Bit hasty to assume it is arbitrary.

 

[Spark]

That's not what I've heard before. An article last year with the Hawkeye people said that it was nothing to do with accuracy, but the fact that "those have never been given in the past".

 

[salman85]

You have to draw the line somewhere.If it was 2.4,people would ask why not 2.39.You can never please everyone at the same time.

Wise words kids.Lead to a happier life.

 

[ankitj]

You have to draw the line somewhere.

You have to? The only source of imprecision can be determining position and velocity of the ball (and since cricket ball is a massive object, Heisenberg's uncertainty principle need not bother us ). Larger the distance the ball has to travel, more is the imprecision magnified. You draw a line to account for that? No. Leave it to the engineers to determine a confidence region for a certain level of acceptable probability.

Problem is when you mix technology and human judgement, that too of those who possibly aren't trained in basics of physics or statistics. This is when you get arbitrary rules like 2.49 m is acceptable even if the ball is hitting the top of the off stump, but 2.5 m is not even if the ball is hitting middle of middle stump. Leave it to engineers once it goes upstairs, just give them a probability level you are happy to accept (95% or whatever). Give them specifications, they will make a tool.

 

[Migara]

You have to? The only source of imprecision can be determining position and velocity of the ball (and since cricket ball is a massive object, Heisenberg's uncertainty principle need not bother us ). Larger the distance the ball has to travel, more is the imprecision magnified. You draw a line to account for that? No. Leave it to the engineers to determine a confidence region for a certain level of acceptable probability.

Problem is when you mix technology and human judgement, that too of those who possibly aren't trained in basics of physics or statistics. This is when you get arbitrary rules like 2.49 m is acceptable even if the ball is hitting the top of the off stump, but 2.5 m is not even if the ball is hitting middle of middle stump. Leave it to engineers once it goes upstairs, just give them a probability level you are happy to accept (95% or whatever). Give them a specification, they will make a tool.

That is a good idea. But what we have is still better than having howlers.

 

[Furball]

Absolutely rubbish article.

The flaw isn't in the system. The fault here lies with Billy Bowden.

 

[Furball]

This is the problem expressed in as few words as possible. It's kind of farcical that Bell would have been given out if he was say, only 2.49 metres down the crease. Assuming that the reason they have set this arbitrary number is that they don't have faith in Hawkeye's accuracy, it only puts further doubt into the viewer's mind as to whether the technology is reliable.

The technology is fine. The problem in this instance was Billy Bowden, who after looking at the review decided that Ian Bell being more than 2.5m down the pitch introduced enough doubt to reprieve him despite being hit in line and HawkEye predicting that the ball would have gone on to hit middle stump halfway up.

That's not a flaw in the UDRS system, it's a serious flaw in Bowden's decision making process.

 

[vcs]

The technology is fine. The problem in this instance was Billy Bowden, who after looking at the review decided that Ian Bell being more than 2.5m down the pitch introduced enough doubt to reprieve him despite being hit in line and HawkEye predicting that the ball would have gone on to hit middle stump halfway up.

That's not a flaw in the UDRS system, it's a serious flaw in Bowden's decision making process.

Yeah, I agree with you. Complete lack of common sense from Bowden there. I'd be inclined to go along with Ankit's suggestion of removing the arbitrary 2.5m down the pitch thing and leave it to someone to design a program that outputs "out" or "not out" based on whether the margin of impact of the ball with the stumps is within an acceptable confidence interval or not.

 

[fredfertang]

Absolutely rubbish article.

The flaw isn't in the system. The fault here lies with Billy Bowden.

I can't agree it's a rubbish article, as it explained to me what, not having been able to watch the game, I didn't fully appreciate about the situation until I read it (sadly I was visiting a BSkyB less elderly relative yesterday afternoon) but I agree entirely that Bowden was at fault, and that UDRS cannot be expected to cope with irrational decision making by the human beings involved

 

[weldone]

Yeah, I agree with you. Complete lack of common sense from Bowden there. I'd be inclined to go along with Ankit's suggestion of removing the arbitrary 2.5m down the pitch thing and leave it to someone to design a program that outputs "out" or "not out" based on whether the margin of impact of the ball with the stumps is within an acceptable confidence interval or not.

This is a brilliant idea.

 

[gvenkat]

The technology is fine. The problem in this instance was Billy Bowden, who after looking at the review decided that Ian Bell being more than 2.5m down the pitch introduced enough doubt to reprieve him despite being hit in line and HawkEye predicting that the ball would have gone on to hit middle stump halfway up.

That's not a flaw in the UDRS system, it's a serious flaw in Bowden's decision making process.

No. you missed the premise of the piece but you have stated that in your comment. I bolded that part. The broader picture we are looking at is the system having to depend on Billy Bowden and not trusting the system itself.

If you are not trusting the technology then let's not even have the UDRS. In this instance agreed the batsman was well forward, 2.5 meters to be precise and still was deemed out by Hawk eye. Unfortunately Bell was declared not out.

The funny thing is if he had been ruled out, The call would have still stayed out. We cannot have that ambiguity. Either trust hawk eye and go forward or else don't do it. The bigger point in discussion is the human intervention.

Hawkeye is a far superior judge than any human of where a ball that has pitched will end up. The cricket community needs to simply embrace this reality and stop fighting the science. Human judgment is affected by a host of things that Hawkeye isn't. If Hawkeye says someone is out, he' should be out. The needless complications bring more frustration to players and fans than is necessary.

The broader picture is the involvement of Bowden or anyother umpire in the UDRS and that's where the system fails.

 

[gvenkat]

Absolutely rubbish article.

The flaw isn't in the system. The fault here lies with Billy Bowden.

Thanks for this Kind comment.

 

[gvenkat]

I can't agree it's a rubbish article, as it explained to me what, not having been able to watch the game, I didn't fully appreciate about the situation until I read it (sadly I was visiting a BSkyB less elderly relative yesterday afternoon) but I agree entirely that Bowden was at fault, and that UDRS cannot be expected to cope with irrational decision making by the human beings involved

Bingo Sir.

UDRS cannot be expected to cope with irrational decision making by the human beings involved

The sad part is the human beings being invovled as part of the system.

 

[marc71178]

Yeah, I agree with you. Complete lack of common sense from Bowden there. I'd be inclined to go along with Ankit's suggestion of removing the arbitrary 2.5m down the pitch thing and leave it to someone to design a program that outputs "out" or "not out" based on whether the margin of impact of the ball with the stumps is within an acceptable confidence interval or not.

From what I read yesterday that is already in place - it has to be hitting the middle of middle to be within the accepted limit when the impact is that far away though. Bell's was actually hitting middle and off.

 

[vcs]

From what I read yesterday that is already in place - it has to be hitting the middle of middle to be within the accepted limit when the impact is that far away though. Bell's was actually hitting middle and off.

Sounds dodgy. It has to be hitting middle of middle if impact is 2.5m away, but can be hitting only one stump, or the top of the stumps from, say, 2.25m? Doesn't make any sense at all.

 

[Woodster]

Let's not forget this system was introduced to eliminate the truly awful decision, ie batsmen that are given out LBW when they've clearly middled it, or given out caught when the ball clearly came off a part of their anatomy other than the glove. The original decision of not out was not a howler, it was difficult to be certain that ball was going to go on and hit the stumps due to how far down the pitch Bell was. However, I understand the technology debate about if we use, we trust it implicitly etc. Not sure you can do that without it being 100% accurate.

It is an issue that two different decisions can be given for the same delivery, I've said this numerous times before, depending who reviews the LBW (for example) and what the onfield umpire has judged, it may result in two different decisions, with a lot of LBW appeals. But I do like referrals that are close calls remaining with the original decision of the standing umpire. I'm not saying the incident yesterday ended correctly, but that may be down to the communication that took place between the third umpire and Billy Bowden.

 

[marc71178]

Sounds dodgy. It has to be hitting middle of middle if impact is 2.5m away, but can be hitting only one stump, or the top of the stumps from, say, 2.25m? Doesn't make any sense at all.

I can only guess that there's something about the 2.5m distance that means there's too much extrapolation involved - may be something to do with what is a normal length of delivery so there's sufficient information to get a more reliable prediction?

Of course on many occasions if it's just hitting one stump then it's deemed not conclusive anyway.

Either way, the key thing to remember in this case is that if UDRS weren't in place, it wouldn't have changed the outcome so this cannot be used as a reason to not employ the UDRS.

 

[Shri]

I can only guess that there's something about the 2.5m distance that means there's too much extrapolation involved - may be something to do with what is a normal length of delivery so there's sufficient information to get a more reliable prediction?

Of course on many occasions if it's just hitting one stump then it's deemed not conclusive anyway.

Either way, the key thing to remember in this case is that if UDRS weren't in place, it wouldn't have changed the outcome so this cannot be used as a reason to not employ the UDRS.

Thats just a cop out.