A quick look at the DRS rule with hawkeye and lbw

There is a significant issue with the way that hawkeye is used for DRS.

There is some doubt as to the exact position of the ball when captured on camera. It's only accurate to the nearest 2mm or so. While that's very accurate, once it's used to create a model, it can be dangerous. As a result there is a margin for error. Then there can be difficulty determining exactly where the ball hits the pad, especially where it brushes the front pad on the way to the second. This means that there is some doubt as to what the actual position of the ball is.

To overcome this, the ICC have ruled that more than half of the ball needs to hit the centre of the wicket. This is a user friendly option at first glance. The boundary is really clear, and the batsman needs to be clearly out in order to be given out. But near the boundaries there are occasionally situations where the ball is clearly going to hit, but instead the hawkeye system calls the ball "umpires call."

This is particularly ridiculous when the ball has hit the batsman on the back foot. In a situation where the ball has only an extra 40cm to travel, if the middle of the ball is just outside the middle of the stump then for the ball to miss the stumps, then the model would have to be out by 5.5 cm. On a distance of travel of 40cm that's allowing way too much margin for error (realistically there would be a significantly less than 1% chance of the ball missing the stumps).

A solution would be to look at a cone that was using a realistic model for the uncertainty. That would be more sensible for the commentators, fans and players to understand, and would actually provide a more sensible answer to the question "would the ball hit the stumps?"

I've put together a short video to demonstrate what I mean as well.

South Africa vs Zimbabwe - things to watch for

Here are 5 things I'm going to be watching for in this match.

1. I really enjoy watching Elton Chigumbura. He's the sort of player who plays to win the match, rather than playing to have a good average. He gives himself the difficult jobs, and then puts everything into them.

2. Will Zimbabwe get Amla early. The Zimbabwean attack is quite suited to most New Zealand grounds, but if they don't get Amla early, then they will struggle to get him at all.

3. Quinton de Kock - can he rein his game in against the slower paced (but subtle and tricky) opening attack of Zimbabwe.

4. Brendan Taylor - Has he regained his touch that made him one of the best batsmen in the world in 2011.

5. South Africa's movement off the ball in the field. De Villiers has made it clear that he wants to see his team moving around more off the ball, like the New Zealand players do. This will be a chance to see if his talk has worked.

Martin Guptill and the form myth

Every season there seems to be a cause célèbre among NZ cricket fans. In 2013 the call was that Brendon McCullum wasn't scoring enough runs, and needed to be dropped. In 2013-14 it was that Peter Fulton wasn't scoring enough runs and needed to be dropped. This season the overwhelming majority of cricket talk in New Zealand has been about one man: Martin Guptill. Apparently he isn't scoring enough runs and needs to be dropped.

In either calls to Radio Sport or comments on the Vietchy On Sport facebook page there have been at least 21 players suggested as being a better option as an opener than Martin Guptill. People have suggested different ways that he might get injured in order to get him replaced in the squad.

But the opinion that Guptill's significantly out if form is not just confined to the uninformed public (I consider anyone that suggest Michael Pollard, Peter Ingram or Kyle Mills as replacements for Guptill uninformed). There have been a number of the country's sports journalists join in. In a quite well written and balanced piece, Andrew Alderson noted that Guptill "struggled for form." Charlie Bristow talked of Mike Hesson needing "to handle Martin Guptill's stuttering form." Mark Geenty commented that the top order was carrying "significance and concern." Guy Heveldt said that Guptill is "under immense pressure to find some form before the World Cup begins." Daniel Richardson said that Guptill is "out of touch", "has done little to inspire confidence" and that his "form is a concern."