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Television killed the umpiring star

What the new umpire's-call rule says about the role of the officials

Kartikeya Date |

At its annual general meeting in July, the ICC decided to reduce the margin of the umpire's-call element in the Decision Review System. The old rule required that at least 50% of the ball must be hitting at least 50% of a stump in the estimate provided by the ball-tracking model. The change, which comes into effect this month, now requires at least 50% of the ball to be hitting any part of a stump, or, as the ICC phrased it: "The size of the zone inside which half the ball needs to hit for a Not Out decision to be reversed to Out will increase, changing to a zone bordered by the outside of off and leg stumps, and the bottom of the bails (formerly the centre of off and leg stumps, and the bottom of the bails)."

The umpire's call has traditionally invited the scorn of a number of prominent players as well as commentators. The rule change is a victory for the view that umpire's call is excessively deferential to the umpire. In this essay, which extends ideas I have written about previously, I consider what this change says about the past, present and future of umpiring.


Contradictions abound with the DRS. It was invented, according to the ICC, to correct obvious umpiring mistakes. But it is used most frequently to litigate on marginal umpiring decisions. The purpose of the player review was to allow players to question umpiring decisions where they knew the umpires had got it wrong. Yet players routinely use the review speculatively, to see if they can get a marginal reversal. The DRS was invented because umpires were deemed to be experts who made clear (or obvious) mistakes from time to time. It was not intended to make up for any perceived shortcoming in an umpire's expertise. It was intended to make up for the human tendency to make mistakes in real time. This distinction is important.

If an umpire lacked expertise, then no matter how many times he or she saw a particular lbw appeal, the right decision would not be reliably reached. But if an umpire simply made a mistake in real time, it would be recognised on replay. As an analogy, think of the times where you have made a mistake adding up two numbers. This is a mistake. It does not occur because you don't know the correct way to add two numbers. If you didn't know how to add, no matter how many times you looked at the problem, you wouldn't know how to reliably calculate the correct answer.

The DRS was not intended to make up for any perceived shortcoming in an umpire's expertise

Not only is the DRS only rarely used for this kind of correction, the process used to identify mistakes - the player review - fails about 75% of the time. At the 2015 World Cup, 583 umpiring decisions were made (including 312 lbw and 229 catches): an umpiring decision is made any time an umpire answers an appeal, so not all dismissals involve umpiring decisions and nor do all umpiring decisions result in dismissals. Eighty-four were reviewed and only 20 of those were successful; 57 reviews were for lbw appeals, of which only eight were successful. According to data provided by the ICC, in all international cricket between April 2013 and March 2016 in which the DRS was used, one in six umpiring decisions was reviewed by players. Three out of four player reviews failed. Umpiring decisions on lbw appeals were reviewed more frequently - about one in every four. Four out of five such reviews were unsuccessful.

Many players, as well as TV commentators, often betray a misunderstanding about the DRS, beginning with the basic question of what it is. In cricket the umpire can choose between two options when answering an appeal - out and not out. The DRS is a system for reviewing the umpire's answer. It is not a system for providing a new answer to the original appeal by setting aside the umpire's first answer.

The DRS is also frequently the catch-all term for the suite of technologies used within the review system, technologies that are also not well understood. The most widespread misunderstanding is about ball-tracking and the notion that the estimate of the path of the ball from pad to stumps is not an estimate but a statement of fact. This is particularly puzzling, since it suggests that players and commentators misunderstand the lbw law. A leg-before decision is built on the umpire hypothesising about an event that never occurs, that never occurred and never will occur.

The question that must be answered on an lbw appeal is: "Had the pad not been in the way, would the ball have gone on to hit the stumps?" The answer to this question is not knowable in the same way as the answer to "Did the ball touch the edge of the bat?" In the case of an edge, the event occurs. The DRS includes technologies that enable an answer to this inquiry. No comparable data can possibly be available in the case of lbw. The estimate of the ball-tracker is just that: an estimate. This is why marginal cases, where the estimate contends that the ball is clipping the stumps, are classified as umpire's call. The probability of an estimate being wrong by an inch is exponentially lower than it being wrong by a quarter of an inch. The point of umpire's call is simply to ensure that only those decisions that can be refuted should be overturned. All other decisions should be allowed to stand.

The rise of the DRS is tied in to the way the authority of the umpires has been undermined by players and broadcasters over the years

The rise of the DRS is tied in to the way the authority of the umpires has been undermined by players and broadcasters over the years Cameron Spencer / © Getty Images

Yet, even Kumar Sangakkara evidently misses this point. Perhaps he was caught up in the disappointment of the moment - his former team-mates had just been denied an lbw thanks to a review by the England batsman when he tweeted: "High time the ICC got rid of this umpires [sic] call. If the ball is hitting the stumps it should be out on review regardless of umps decision." Later he added: "is a feather of a nick marginal if it doesn't show up on hotspot but only on snicko? Then why use technology." Sangakkara is not alone in misunderstanding that when an lbw review returns umpire's call, the ball-tracking estimate is telling us: "This may go on to hit the stumps, but it cannot be said with sufficient certainty."

Now it is true that what the ball-tracking companies consider to be sufficient certainty and what the ICC considers to be so is not the same thing. Different providers use different methods for predicting the ball's path. They are also not equally confident about the reliability of the predictions. Ian Taylor, the head of Virtual Eye, has previously suggested that TV umpires be given an override switch that allows them to ignore the ball-tracking estimate in certain circumstances. Paul Hawkins, of Hawk-Eye Innovations, is far more confident of his company's ball-tracking predictions.

But if we take the criticisms of Sangakkara, and Shane Warne and Ian Botham among others, to their logical conclusion, then by eliminating the umpire's call, and with it the idea of the marginal decision itself, there is no longer any need for the umpire. If the review is for the appeal and not the decision, then why is the decision necessary in the first place? Why make umpires stand in the sun for six hours if their expert judgement, from the best position in the house, is not needed?

Why not use only DRS technologies instead of an umpire? Almost every single thing the umpire does on the field can now be done from beyond the boundary. The umpires could sit in a nice air-conditioned office in the pavilion with a dazzling array of screens and controls. They could even operate the electronic scoreboard from there, instead of signalling boundaries and extras to the scorers.

A leg-before decision is built on the umpire hypothesising about an event that never occurs, that never occurred and never will occur

One practical answer is that these technologies are expensive. We will still need umpires at the lower levels. But without the incentive of being able to become an international umpire, what might happen to the quality of umpiring at the lower levels?

As a scientific matter, if one is to consider replacing the umpire with such technologies then the responsible thing to do is to consider two kinds of error. First is the margin of error of the technology itself. Take the ball-tracker. The amount of information available for each delivery is not exactly the same. For instance, the faster the delivery, the fewer the number of frames of video available from which the path of the ball can be traced. And because the same amount of data is not available for each delivery, all projected paths cannot be predicted with equal certainty.

This is not to say that most paths cannot be predicted with sufficiently little uncertainty. In an interview in 2011, Hawkins explained that the accuracy of the prediction is more binary than one might imagine. There is either sufficient data for a reliable prediction or there isn't. One example of a situation where there isn't sufficient data is for yorkers. The ball-tracking system designates any situation in which the distance between the ball's pitching point and the point of impact is less than 40cm to be an "extreme" lbw. A mistake by the ball-tracking system in an lbw review involving Shan Masood about two years ago may have been due to this condition.

Before ball-tracking, the decision against Masood could have been argued two ways - one, that the ball was very likely to miss leg stump, and the other, that Masood had moved a long way across and was hit on the back heel inside the crease. The ball did not have much to travel. This would have introduced doubt into the idea that the ball would have missed the stumps.

If we eliminate the idea of umpire's call, and with it the idea of the marginal decision itself, is there a need for the umpire?

If we eliminate the idea of umpire's call, and with it the idea of the marginal decision itself, is there a need for the umpire? Richard Heathcote / © Getty Images

In the ball-tracking era, with the increased number of mini-decisions in the chain between the original appeal and the final decision, there are more points where people can make mistakes than before. What's more, there are more people who can make mistakes. The Masood lbw did involve operator error according to Hawk-Eye. The upshot of all this is that the cricketing question of whether or not the decision against Masood was reasonably defensible was set aside in favour of doubts about the plausibility of the ball-tracking estimate.

Hawk-Eye did once suggest visualising the confidence of each prediction by drawing an "uncertainty ellipse" around the ball. In cases where there was sufficient information to make the prediction, the ellipse showing a calculated error would be extremely close to the ball. Showing the ellipse, however minor the error might be, would continually remind viewers of two facts: first, that the animation they were watching was an estimate, and second, that the estimate was probabilistic. This was rejected by broadcasters, who preferred a "definitive" visualisation.

I am inclined to accept that the mathematical prediction models are generally reliable. As more testing is carried out, and with advances in hardware, these models will continue to improve. But even if we assume that the model is good, and its least confident prediction is still sufficiently confident, we also have to make allowances for shortcomings - those factors it is not designed to account for. I am not referring to atmospherics, or the peculiar traits of a cricket ball at different stages of its existence (the model's solution of tracking movement has an elegant way of accounting for these). Instead I refer to, for instance, the limits of video - the path of the ball from the bowler's hand to the batsman is constructed using multiple video frames from multiple tracking cameras; or the non-standard nature of cricket stadiums, which could introduce limits to the extent of calibration possible; or the difference in the quality of video available in different countries.

Every city in the world that requires the certification of building designs before construction requires that concrete structures be "over-designed" to include a factor of safety. This is usually a matter, for example, of increasing the calculated beam depth for a given span by a certain percentage. This is done to cover for uncertainties that the calculation cannot take into account. The umpire's call is similar.


Connoisseurs and administrators have dreamed of using technology to help umpires for decades. But the development of the DRS is not solely the result of an innocent, abstract desire to help umpiring. Its evolution is a direct consequence of the authority of the umpire being undermined by players, aided and abetted by broadcasters. It was not inevitable that technical assistance for umpiring decisions should take the form of a review initiated by players. Nor was it inevitable that the very technologies used to enhance the entertainment value of the television broadcast should become tools of adjudication.

Umpires are right to be fearful. Their authority has been systematically dismantled from the commentary box

The very design of the DRS betrays its impulses. If the point of the system were to correct obvious mistakes, why would such sophisticated technologies be necessary? Shouldn't an obvious error, by its definition, be obvious? Instead, it appears that a central impulse was to ensure that the very technologies that were used by broadcasters to litigate umpiring decisions be used in the review. Given the pressure the umpires had been placed under, it would not have been viable to use a system of reviewing decisions that did not include these technologies.

Consider now examples of the oldest form of review - requesting replays for run-out calls - to see how umpires have begun to question their own expertise. Matters have reached a stage where they reflexively draw a TV screen in the air even for the politest, mildest appeals, where it is patently clear the batsman is in. The replay often shows him well inside the crease, or even past the stumps. There are arguments to be made for being safe rather than sorry, but there are instances when umpires signal for the replay even as the batsman is walking off to the pavilion. This is motivated by fear, not caution.

And umpires are right to be fearful. Their authority has been systematically dismantled from the commentary box. To see why, we must understand the model of the TV "argument", the central feature of which is balance, not accuracy or depth or nuance (which lead to complexity, which is boring for TV).

If one person takes the position that the earth is flat, and the other that the earth is round, then a "balanced" argument treats both positions to be equally valid. Here's how it might happen during commentary. An important batsman is given not out at a crucial stage. One commentator makes an effort to explain why the decision was marginal and why it might have reasonably gone either way, that the umpire did not make a mistake. The co-commentator, either by way of "balance", or in an attempt to live up to a TV persona, responds by saying he thought it was out and the fact that it was not given is a mistake. One side concludes the earth is round. The other disagrees. If there is time, they have a "debate", which usually amounts to the two claims being restated in different ways until time runs out.

The "balanced" argument comes with the following corollary in cricket commentary - as long as an umpire is praised for getting a decision right, it is perfectly reasonable to excoriate him for getting a decision wrong. The rightness and wrongness of marginal decisions is, by definition, doubtful. But the manufactured certainty of a visualisation like the ball-tracker enables a thorough excoriation, minimising marginality. One commentator will offer the careful, nuanced live commentary. The other will see the ball-tracker depicting the ball clipping leg stump and say, "This is where umpire's call saves the batsman despite a bad original decision." Of course, if the ball-tracker shows the ball missing by a whisker, the same commentator will praise the original decision. The difference between the two stances is often no more than a fraction of an inch. There is no cricketing merit in having such divergent opinions about instances separated by fractions of an inch, but it makes for great TV; never mind that it undermines the authority of the umpire.

Under the DRS not only are there more points where people can make mistakes than before, there are more people involved in the process, who can make mistakes

Under the DRS not only are there more points where people can make mistakes than before, there are more people involved in the process, who can make mistakes © Getty Images

Too many commentators seem willing to accept the idea that a decision is worth reviewing just because a player does not like it. If not, the vast number of bad player reviews would bother them at least as much as the marginal lbw decision going against their team seems to. They don't. You never hear of how consistently unsuccessful players are at reviews. That's one statistic commentators rarely track.

Their job precludes them from saying "It could reasonably have gone either way" too often. That response makes everybody but the most serious cricket fans deeply unhappy. And if only serious cricket fans watched cricket, elementary economics says that it would not interest most broadcasters. The point is not that commentators are inherently bad. That matters are not as simple as this is palpably evident from the fact that the same commentators sound different depending on the broadcaster they work for. Rather, the point is that the DRS is the product of the complex interplay of cricket and the lucrative show business of its broadcast. Commentators constitute the high-profile face of the show-business side and usually have a deep history on the cricketing side, and hence are central characters.

As conclusion, here is an idiosyncratic history of umpiring, told through three umpiring decisions and their presentation. It constitutes a prehistory of this latest change in the rules. On the fourth evening at Adelaide Oval on a day late in 1999, Sachin Tendulkar was given out lbw after ducking into a Glenn McGrath bouncer. The ball didn't rise on a wearing, pre-drop-in-era wicket. Ian Chappell and Sunil Gavaskar were on commentary, and after describing the action, Chappell said:

"Dangerous lbw decision for an umpire to give because there are so many moving parts. It's not like the batsman being hit on the pad. There's a lot of movement when the batsman's ducking like that. It's hit him up under the back of the arm. [Pauses as the ball leaves McGrath's hand and reaches Tendulkar] Oh, it's not the easiest decision to give at all. Because with all those things moving, you've got to be very sure."

Gavaskar was interested in why Tendulkar chose to duck. He pointed out that the short leg probably worried Tendulkar and made him choose not to play at the ball. Chappell and Gavaskar had been discussing, even before the appeal, how ducking was likely to be risky given the uneven bounce. There was no Hawk-Eye. But between the video and the commentary, it was clear to the viewer what had occurred. Australia had set a trap and it had worked. The decision McGrath won was bold but reasonable. It was possible to reasonably disagree with Daryl Harper, but it could not be successfully argued that he was definitely wrong.

Too many commentators seem willing to accept the idea that a decision is worth reviewing just because a player does not like it

Nearly 12 years later in Mohali, Tendulkar against Pakistan in a World Cup semi-final. In the 11th over of India's innings, Saeed Ajmal got a ball to grip and turn past Tendulkar's forward defensive. On commentary, even as Ajmal and Kamran Akmal were seized by the appeal of their cricketing lives, Sourav Ganguly's instinctive reaction was that it looked very close. Sure enough, umpire Ian Gould gave it out.

It was a perfectly reasonable decision. Any umpire who made the same decision could not be faulted. But here was a wrinkle. The ball-tracking estimate showed that the ball would have missed leg stump by what seemed to be a few angstroms. This time the intimately intertwined apparatus constituted by the umpires and the broadcast told us simply that Gould was wrong and Tendulkar was safe. Leg-before decisions were no longer reasonable judgements by human beings. Ganguly's instinctive reaction on commentary was lost amid the manufactured certainty. Cricket's broadcast no longer had time for the subtle idea that close appeals are close because they are close to being out, while close decisions are close because they are more or less equally close to being out and not out.

Four years later, during the knockout stages of the 2015 World Cup, we, the viewers, were finally allowed into the inner sanctum. While a review was in progress, instead of hearing commentators, we heard what the umpires said to each other.

"Let's look at the no-ball. Yes, that looks fine."

"May I see spin-vision when you are ready?"

"Let's see the ball-tracker when you are ready."

"Pitched outside leg."

The ICC's rulebook governing the DRS prescribed these questions. The role umpires were playing could have been played just as well if they were all sitting in a room in front of a television; in the age of the DRS, the umpire has gone from being the expert match manager to all-purpose match clerk. On its own, the change in umpire's call is not the worst idea, even if it is an unnecessary change. But it is a signal that a bad argument has won - another milestone towards the end of the umpire's expertise.

Kartikeya Date is an academic researcher. He writes a cricket blog and is a contributor to ESPNcricinfo's Cordon





  • POSTED BY cricfan62240996 on | December 15, 2016, 9:09 GMT

    The gentleman is being taken out of the gentleman's game. SAD! I read some similar articles on flipside news.

  • POSTED BY Shekhar.Gupta on | November 3, 2016, 6:37 GMT

    I disagree with: (a) It is not possible for ball-tracker to reliably decide on LBW, (b) DRS showing umpires being far more right than wrong, hawk-eye is unnecessary, and (c) technology is reducing umpires to cap-hangers. (a) Technology to predict trajectory of a missile is available for long and for a cricket ball over 22 yards it can be far more accurate than human eye. (b) Umpires adjudicate the game, not participate. An avoidable mistake on their part may well turn the match on its head for no fault of players. (c) Umpires must be respected for their expertise of interpreting the laws and ensuring spirit of the game; their writ cannot run against technologically provided evidence. So, provide for TV umpire to decide in the areas prescribed by ICC or when a field umpire requests but only when relevant technology has been well-tested as reliable by ICC. Broadcasters may show replays only in such areas. And end the DRS but by embracing technology, not by rejecting it.

  • POSTED BY Cricinfouser on | November 2, 2016, 6:49 GMT

    Like it or not, traditional umpiring at the top level is almost dead in the water. The only thing preserving it is the ridiculous limit of 2 incorrect challenges and umpires call. In my view, this should be replaced by a system where the umpire takes responsibility to use the technology anytime he has a doubt, rather than make teams challenge. As happened with runout calls. one or two high profile errors and umpires will realise they need to use the technology for all but the most obvious decisions. This will restore the umpire to being in charge and save embarrassment for poor decisions. Everyone wins.

  • POSTED BY SG70 on | November 1, 2016, 21:09 GMT


    Because otherwise there is simply no reason for all the ambiguity , doubt , confusion and aggravation surrounding the use of ball-tracking. That said the makers of the Technology have done a very Poor PR job in explaining the technology in very simple terms to the public. This is the primary reason for all the distrust. They should step forward and put out a simple youtube Video demonstrating how the system works and even show testing clips that I explained in my earlier posts to dispell all the myths.


    Lastly I dearly hope and pray that the DRS trial during the England series goes well.

  • POSTED BY SG70 on | November 1, 2016, 19:20 GMT

    @RPOSH <br> The problem with the article is that it compares adding 2 numbers to deciding a LBW. Thats just plain WRONG.Anybody that has seen sufficient HawkEye replays will understand this.

    Second problem is that ...The Author states claims: "The estimate of the ball-tracker is just that: an estimate."

    Well it just is *NOT* an estimate. Just isnt. It is Based on simple physics laws that say a ball *AFTER* (let me re-emphasize the AFTER one more time) hitting the ground and the ground having done its part will travel in a trajectory that is purely a function of Angle and Speed. Both of which can be accurately determined by the ACTUAL data captured.Unless the author is in the know that these 2 cannot be accurately measured there is no way that stmt can be backed up. Can someone confirm if this is the case ? (contd)

  • POSTED BY Ropsh on | November 1, 2016, 17:06 GMT

    Finally, an article that understands the limitations of the Predictive path! This is why the MIT study needs to be published for review by competent statisticians, rather than those who can barely add up.

    Until the study is published, the Predictive path must be taken to be no more accurate than a blind man throwing a dart.

  • POSTED BY Nasir_Mahmood_Malik on | November 1, 2016, 15:19 GMT

    Appreciate the energy you have put in to explain all this. But I beg to disagree.

    The use of technology was brought in only because "umpires are only human, and can make mistakes". But after having involved technology, if the decision falls in the borderline, how smart and logical it is to disregarding technology altogether, and accept the same human's decision to be correct. The earlier rule of "benefit of doubt goes to the batsman" was fair and evened out in a reasonable span of time. The shift to "benefit of doubt goes to the umpire" is un-digestible.

  • POSTED BY DrJez on | November 1, 2016, 14:12 GMT

    @Neel_123, @ Cricinfouser. @and others. You misunderstand ball-tracking. Hawkeye does not predict trajectory based on previous deliveries. Hawkeye only looks at the ACTUAL movement of the ball AFTER pitching, and merely predicts a continuation. The pitch is utterly irrelevant. In the case where the ball hits the pad on the full, there is an agreement that the ball will continue on its current path, with no deviations whatsoever on pitching. So again, the pitch is irrelevant.

  • POSTED BY SG70 on | November 1, 2016, 14:05 GMT

    @GMSJGMSJ : This is how it can be tested and verified !


    1. Using balls that are coated with a dye/paint that leaves a mark on white Screen (instead of stumps) ask Various Bowlers (fast/spin) bowl at the screen without any batsman at the other end. Note down the points of impact on the screen! These are the actual points of impact. <br>

    2. Capture ball tracking data with the Ball tracking system during step 1 above. <br>

    3. We verify for each ball if the point of impact on the white screen matches with what the Ball tracking system says. If not the test fails. <br>

    4. Now to test the predicted part of the Ball tracking system. Remove the data points for the last 2-3 meters of data from the Ball tracking system to simulate LBW and see if the mathematically derived extrapolation (using rest of the ACTUAL data from bowlers hand to lbw impact ) leads to the same impact point as noted in point 1,3 above. If it does we have a winner!! Rinse repeat for all kinds of pitches + bowlers

  • POSTED BY SG70 on | November 1, 2016, 13:57 GMT


    That Analogy is just sooo wrong (Traffic vs Ball tracking). Because vehicle traffic is truly random. Whereas in Ball tracking Hawkeye actually has the REAL data for about 80% of the journey that a ball undertakes after leaving the bowlers hand and headed towards the stumps. Most importantly the Actual data includes what actually happened to the ball *AFTER* it pitched and bounced hence the PITCH effect is already known and is part of the ACTUAL data (This is the crucial point that most people forget ). The other component is Speed. This is also ACTUAL.. Now given that the ball does not swing AFTER pitching and especially since there is just 2-3 meters at best to travel the balls path can be mathematically determined (and tested and verified !!) based on the actual data that was gatehered as mentioned above. This is just pure science and mathematics problem. Its not a statistics/probability problem.


  • POSTED BY SG70 on | November 1, 2016, 13:26 GMT

    "What does the umpire's call rule say about the role of the officials?" "TV Killed the Umpire"


    Well this was bound to happen and you cant blame anyone but the long list of incompetent ICC umpires that forced the hand of the authorities to do the right thing. Believe me there is nothing charming about the "Human" element ... the tragi-comic Cliche that was thrown around (For Example ) when Steve Bucknor officiated in his last Test Match making sure he did everything in his powers to wreck the Sydney Test Match beyond repair. Thank lord that there was DRS in the BD vs Eng series else the outcome would have been completely different given the numerous decisiosn that were over turned !!

  • POSTED BY John-Price on | November 1, 2016, 11:35 GMT

    @ VisBal on . Thank you for your reply. I followed most of it, but couldn't understand why you say 'Overall, ALL LBWs would be Not Out on review. ' I don't see where that statement comes from.

    Never mind, I fully accept that there are uncertainties in DRS, that is the way of the world. My point of view is that we presently have two systems (umpires and DRS) when we only need one and this leads to confusion and acrimony. I am entirely certain that the best system is DRS, on the basis that any uncertainty is only a fraction of what it is when umpires try to work it out themselves - so I would always go with DRS.

    A co-lateral advantage is that players are more likely to accept a decision when they can see an apparently definitive answer on a TV screen. You see this in tennis with line calls. I don't think anyone believes that hawk-eye is 100% but players accept the results and get on with the game because it is free from systematic bias and the same for everyone.

  • POSTED BY gmsjgmsj on | November 1, 2016, 7:22 GMT

    Wonderful insights by Karthikeya Date. To go more into the analogy of the ball tracking, let us imagine a person going from point A to B in a city. Though there are many routes, the most popular or most logical is usually followed. Now there is the mode of conveyance which is akin to the speed of the ball, clutter of traffic which is akin to the movement in the ball and the exact time of arrival which is akin to the point of impact. The time of arrival is variable to the mode and the traffic and there is no most certain method to say if you will arrive on 1.15 or 1.16 or 1.14. Now that you have arrived at point B (the point of impact) you now have to predict what is that you would have done if - (a) you arrived late and it consequences (b) arrived early and it consequences and (c) arrived on time. Obviously any math model can only predict but can never offer absolute certainty. DRS was introduced to eliminate howlers. What is a howler is the "million dollar" objective question!

  • POSTED BY cricfan21876810 on | November 1, 2016, 6:55 GMT

    I have a question about DRS. When the ball just misses the leg stump shouldn't that be stay with the umpire's decision just like when it clip leg stump.

  • POSTED BY Neel_123 on | November 1, 2016, 5:17 GMT

    DRS won't work in LBW even if there is a significant improvement in hardware part; computers don't have the 'common sense'. For a simple LBW appeal, there are too many variables: nature of pitch - venue, which day of the test, footmarks, roughs, air flow, the extent of pitch deterioration (spongy bounce, etc.). Any ball hitting the pad after pitching near to half-volley or full will be impossible to predict accurately by any set algorithm.

    And then comes the problem of tinkering the algorithm with the passage of the game: An umpire (or bowler) will learn in REAL TIME the progress of bounce, spin, and swing of the ball. A mathematical algorithm in DRS, though possible but I highly doubt, is learning with each ball and modifying the equation. I wonder if the hawk-eye program works on a 4th day Nagpur pitch on same equation-set as on a 2nd day Perth pitch!

  • POSTED BY Cricinfouser on | November 1, 2016, 4:55 GMT

    My concern with ball tracking is this: The pitch will change during the course of the match and will cause the ball to move differently (which will depend on the type of the pitch prepared). Which part of the ball hits the ground also can affect the subsequent trajectory significantly. How does the model incorporates this? Also as mentioned by the author, the air & moisture will affect too. Do they calibrate the model under different conditions of the pitch?

  • POSTED BY Tests-are-best.Bounderno:6 on | November 1, 2016, 4:38 GMT

    In my humble, and no doubt unpopular, opinion, the use of technology has changed cricket for the worse. For me, what I was taught as a youngster learning to play the game was that "the umpires decision is final", to be accepted without question or any show of dissent. This was one of the most important tenets of cricket and also I believe of rugby union. Mistakes are made in all walks of life and umpires are human and that fact has to be borne in mind; some mistakes will be to your benefit, others will not. And it is clear from this well written and researched article that, in fact, technology has still not adequately solved the problem, doubts remain.

    Conclusion: cricket was played long before television and survived and grew into the greatest of all games throughout the world. Stop the use of technology and return the conduct of cricket to the on-field umpires.

  • POSTED BY Z-Niazi on | October 31, 2016, 19:02 GMT

    A simple way to check and adjust the accuracy of the ball tracker would be to record several thousand deliveries with a known path, i.e without the batsman. After recording, they should edit each video to insert a batsman figure to depict a point of impact. They should then let the "ball tracker" make it's decision based on it's algorithms. By comparing that decision to the "known" ball path, they should be able to improve the tracking algorithms for a more accurate one. My 2cents worth....

  • POSTED BY VisBal on | October 31, 2016, 18:59 GMT

    (cont'd.) To use DRS for LBWs in the way it was intended would involve statistical evaluations of an order that the average viewer does not care for. What you will get out of ball tracking is a probability ellipse of the position of the ball as it passes the plane of the stumps. This in turn can be converted into a probability that the ball would have hit the stumps. Now, how much of the ball would need to hit how much of the stump to dislodge a bail? (That is the test we are working against: If the batsman had not impeded the motion of the ball with his body, would he have been bowled?) This is obviously speed dependent, but faster balls have more uncertain trajectories (data insufficiency error). Overall, ALL LBWs would be Not Out on review. Hence, we need to set standards for overturning a decision. Due to the nature of the initial decision (null hypothesis), the standard to overturn is different in both cases.

  • POSTED BY VisBal on | October 31, 2016, 18:52 GMT

    @ John Price: "If you check a decision using technology which gives a firm answer and then ignore that answer on the basis it was all so close that a proper answer is impossible is a ridiculous position to get into. "

    The problem with ball tracking technology is very much what you have left unstated. As noted by the creators of at least two ball-tracking devices, the projected trajectory of the ball is an estimate. The trajectory up to the point of impact is measured. As with any estimate, it has a margin of uncertainty. At each point along the trajectory (calling z the axis from stump to stump), there are uncertainties in projection along both x and y directions. The vertical uncertainty gives the uncertainty in bounce and the horizontal uncertainty is the uncertainty in lateral movement. If the ball swings or spins significantly, you get a larger x-uncertainty. What we get on screen is average trajectory of the ball. (cont'd.)

  • POSTED BY dejfrith on | October 31, 2016, 17:30 GMT

    No need for umpires? Who would hold the bowler's sweater and cap, and count to six? Fact is, umpires are so busy nowadays slapping their chests with crossed arms that no-one could logically challenge the fact that without the revelations and clarifications provided by the analysis machinery and the off-field umpire there would be many bad verdicts which unjustly swing the course of matches and of players' careers. It was apparent as long ago as 1982, at Sydney, that there was a pressing need for analysis by umpires "upstairs" to be introduced: John Dyson was run out by a yard in the opening over, but given not out. He batted a further five hours, ensuring Australia retained the Ashes. I was the first to cry out (in Wisden Cricket Monthly) for something to be done, having already seen countless miscarriages of justice over the decades. It made no sense now that they could be avoided. But administrators have traditionally been slow to see the obvious - unless it means more money.

  • POSTED BY John-Price on | October 31, 2016, 15:25 GMT

    When an umpire is reviewed and it is an umpires call, this is often felt to be a vindication of the umpires decision and they are to be congratulated. In act, it is no such thing. It is impossible or an umpires to get such a decision wrong as whatever he decides is deemed to be correct - he may as well toss a coin. And that is what is unsatisfactory about the whole idea. If you check a decision using technology which gives a firm answer and then ignore that answer on the basis it was all so close that a proper answer is impossible is a ridiculous position to get into.

  • POSTED BY Cricinfouser on | October 31, 2016, 15:13 GMT

    Why you need an umpire in the middle when he can only walk after six balls have been delivered?

  • POSTED BY Jhantor on | October 31, 2016, 14:18 GMT

    Very nice piece. Thank you.

    In my mind the answer is simple: completely remove the DRS. The game was so much more enjoyable without it. Remember when the raising of an umpire's finger meant the batsman was out? These days fans have to wait around while the delivery is analysed frame-by-frame, as if that's what we pay money to see. Not to mention the celebrations at the end of almost all test matches are now stunted due to the fact that every 10th wicket decision is reviewed. Hey, if they've got reviews they might as well use them, right?

    However, I agree with previous comments. If we are to persist with the scourge that is the DRS then all decisions must be made on-field. That includes run-outs, no-balls, catches, etc. If a player is unhappy with the decision then they can review. The current situation with both umpire and player reviews is crazy. We've almost reached a point at which the fall of every single wicket is reviewed in some fashion.

    I also agree CRICINFOUSER@12:59

  • POSTED BY RichardStone on | October 31, 2016, 13:57 GMT

    This is an outstanding article and perfectly summarises the issues I've had with DRS since it was introduced.

    I've always felt that the ICC need to make a decision on what the DRS is. Is it there to eliminate "howlers" or is it there to improve decision-making? If it's the former, then why are there 2 reviews and why are they reset after 80 overs? 1 review per match should be sufficient; that ensures that players will only ever use it in situations where they're certain a mistake has been made. No more of this "might as well review it" nonsense.

    If, on the other hand, the intention is to improve overall decision making then all decisions should be made by technology. We're in a middle ground at the moment which doesn't work.

  • POSTED BY skiddy1903 on | October 31, 2016, 13:54 GMT

    a good read but I'm afraid I disagree with a lot of it. Why should the umpires be protected from mistakes, however marginal? The article is correct to state that lbw is a prediction about an even that will never happen and therefore there is margin for error. Up until the last 10 years the best tool available to make that judgement was a man in a white coat standing 22 yards away. Now the best way to make that judgement is with ball tracking technology and despite there still being a margin for error it is vastly reduced compared to relying on the umpire. Cricket needs to either embrace it or get rid of it. DRS was supposed to produce less debatable decisions but the way it has been used means if anything there are more. Tennis uses ball tracking and relies on it's accuracy 100%. 1mm in or out and it's accepted. By trying to include a margin of error in deference to the umpires cricket has made a total muddle of it.

  • POSTED BY RustomPavri on | October 31, 2016, 13:09 GMT

    Good article. Being a cricket connoisseur and viewer of many decades, I feel the best way to end this debate is to remove the ball tracking technology completely. For LBWs, I feel reviews should be used only for the obvious howler of inside edges. With ball tracking comes in the fuzzy idea of whether 50% of the ball is hitting 50% of the stumps. Let that projection be inside the umpire's mind because players are using this more as a tactical ploy and taking a chance with the ball tracking technology.

  • POSTED BY cricfan94624284 on | October 31, 2016, 12:49 GMT

    such a nice article it is

  • POSTED BY Andymc2 on | October 31, 2016, 12:23 GMT

    One problem with the whole "eliminating howlers" concept is that howlers are far from well-defined. There isn't some obvious divide between 'good decisions or ones that could go either way', and 'howlers'. Rather, there's a continuous spectrum of decision quality. Even for supposedly discrete events like faint edges behind and inside-edges-on-LBWs, there are clear nicks, edges that make a noise but don't leave a hotspot, edges that touched the bat but couldn't be felt, LBWs where the ball nicked the bat but only _after_ hitting the pad, and so on. Even without gambling, players would make mistakes with DRS. For a long time, I thought that only having 1 review per side (to discourage gambles) plus Umpire's Call decisions *not* leading to a lost review (also suggested by Itismenithin) would solve this, but now I'm not so sure.

  • POSTED BY itismenithin on | October 31, 2016, 11:51 GMT

    I would like to see the following changes regarding DRS

    1) Include run-outs and stumpings under DRS, far too many times umpires refer it to the 3rd umpire which brings unnecessary stoppages in the game. on-field umpires should always make a decision(out or not-out), leave it to the the players to challenge it if not satisfied with the decision. 2) in case of umpire's call the team should not lose the review, this would also eliminate the need for resetting the number of reviews after 80 overs in test matches.

  • POSTED BY Cricinfouser on | October 11, 2016, 12:59 GMT

    A very fine article on a very important subject. I have a suggestion, when it comes to DRS for LBWs. The decision should be overturned (from out to n.o) when there is a gap of a ball between the predicted path and the outer edge of the stump. Similarly, it should be overturned from N.O to Out only if the ball is hitting at least the inner edge of the off/leg stump.