Match preview 1st ODI NZ vs SA, Mount Maunganui,

The circular Bay Oval, Mount Maunganui

The countdown to the World Cup finally feels like it's started for real. South Africa are touring New Zealand for 3 ODI matches that are more a means to an end than an end in themselves.  Both teams say that they want to win these matches, and the players who get on the field definitely will.  But they are both aware that the real target is the World Cup.

Surprisingly this match is being played at Bay Oval in Mount Maunganui. It's the 4th ground in the Northern Districts area to hold an international match, and is not going to be used in the World Cup.  However, it is in New Zealand's fastest growing region, and is likely to be a place where a lot of international cricket will be played in the future.  It is also on the east coast, so it is a lot less likely to be rained off in spring time than somewhere like Auckland or Wellington.

As there has never been an international at the ground, there are some aspects that are hard to predict. A par score for the ground really has not been established at this level, and almost all of the players will go in without too much baggage (positive or negative) at the ground.

There were a number of warm up matches played there, and we can tell some things from those.

Firstly, bowlers that tend to bang the ball in were punished.  It seems that the fuller the pace bowlers bowled, the better they did. Secondly the scores were all over the place. Some teams were scoring 300+ while others were struggling to pass 150.  Also, the spin bowlers took lots of wickets but (with two exceptions) went for lots of runs. The two exceptions were Daniel Vettori and local boy Jono Boult (brother of Trent)

The ground is an interesting shape, particularly given it's name of Bay Oval. It is a perfect circle. The boundary is 68m from the centre of the pitch in every direction. This means that it has a straight boundary of 79m and a square boundary of 67m. This obviously favours players who are good at playing the hook, cut and scoop shots (which probably explains why bowlers who bang the ball in get punished).

I've looked through the records of the players at similar shaped, coastal grounds in the past 3 years and there are three names that feature at the top of the list: de Villiers, McLaren and well ahead of all else, du Plessis. The top New Zealand name is Williamson (who is not playing) followed by Neesham.

If I was looking to make a couple of bets, I'd look at putting some money on both du Plessis and McLaren to be top scorer. While it's guaranteed that at least one of these bets will fail, I think it would be a sensible move to cover both.  At time of writing, du Plessis is paying $4.50 and McLaren is paying $26 to be top scorer at the NZ TAB. I think this is good money for both of them. du Plessis has gone past 90 in 5 of his last 9 ODI innings. That's compelling form. I'd look at McLaren for a different reason.

The ball is likely to swing at Bay Oval. It's overcast, with showers likely. The tide will turn at about 11:00, an normally the ball swings around the turn of the tide (either just before or just after). Trent Boult grew up in Tauranga so this is his home ground. If he starts getting the ball to go round corners (as he can) he is almost unplayable. In the matches at the Champions League T20 when the ball swung, he was almost unplayable. To go with that, Kyle Mills has been a beast at similar grounds in recent times. He's averaged 11 at an economy rate of under 4. To back that up, in one of the warm up matches (for Auckland against Afghanistan) he took 2/14 off 7 overs. Mitchell McLenaghan is not in such form, but he has a good record against South Africa, and the ability to hurry up batsmen.  I think it's actually quite likely that New Zealand will take early wickets, and South Africa will need to rebuild. That will create a platform for someone like McLaren to succeed.

As far as New Zealand's batting goes, it is a bit difficult to make too many predictions.  Despite his game being suited to grounds like this, Brendon McCullum has never really been successful at this sort of ground. Neesham is opening for the first time, so that will test his technique more than coming in at 6 does, especially against Steyn, Morkel and Philander (Steyn has the second best figures at grounds like this, after Mills, with an average about 18 and an economy rate just under 5). The other interesting selection is Dean Brownlie. Brownlie is particularly good off the back foot, and has had some success against South Africa, but in every large innings that he has put together, he was dropped early (often more than once). If he gets started, he might be worth putting some money on for NZ top scorer, but I certainly wouldn't back him until he made it to 25.

The other thing to watch out for in this match will be the rain.  There may be some showers early on, but it's quite likely that there will be some serious rain in the evening. This means that there is a reasonable chance that the game will be called off early, and Duckworth-Lewis will need to be used.  I'm a big fan of the Duckworth-Lewis system, but it does hurt teams with good batting depth.  The two teams in world cricket that it works against the most are these two. As a result, the team that bats first is likely to have a slight advantage if it rains.

If I had $50 to bet on this match, I'd suggest these:

1. AB De Villiers to outscore Hashim Amla $10 at $1.92
2. Total match run outs over 1.5 $10 at $3.00
3. Faf du Plessis top South African scorer $15 at $4.50
4. Ryan McLaren top South African scorer $5 at $26.00
5. Whoever bats first to win the match $10 at what ever the odds are post toss.

(all odds from the NZ TAB at the time of writing)

Form is temporary?

Faf du Plessis

“Form is temporary, class is permanent.” It’s a cliché that is fairly frequently repeated. But can we measure form.  But can we measure form, and are some players more prone to big swings in form than others?  In the press conference after day 2, Faf du Plessis said

“It’s nice to average 110. But I understand it’s a good time for me and I need to score as many runs as I can because there’s going to come a time when you don’t score as many runs.  I’m in a little bit of good form and just have to make the most of it.”

It made me wonder if du Plessis was actually a player who had been prone to streaks of form.

To do this I had to find a method that would differentiate between a player being streaky and a player being inconsistent. 

An inconsistent player might have scored: 108, 41, 8, 0, 29*, 37, 6, 114*, 5, 4, 102.   

Whereas for a streaky player that might have read:  6, 0, 37, 108, 41, 102, 29*, 114*, 5, 4, 8.  

One of them has had a hot patch, while the other one has just occasionally scored runs.

In order to test for this I looked at the 15 innings rolling average, and compared it to the cumulative career average.  (both of these terms are explained in the glossary) I found the difference between these two averages at every point in a career where they both existed and then averaged this out.

What this gave me was how far away (either above or below) from the career average a players recent average was. This then gave me a number to describe how streaky a player was.  The difficulty then was knowing how to interpret this number.  Players who tended to get a larger variation in scores would get a higher average difference than a player who was equally streaky, but much more consistent.

As a result I then found what that number was for 1000 random arrangements of the batsman’s innings, and how the average difference compared to those.  This allowed me to accurately look at a player’s streakiness.

I decided to look at first class innings, as du Plessis hasn’t played sufficient tests to be able to tell anything yet.  Also there is a purity to first class results that comes from the similarity of situations that a batsman find themselves in.  In limited overs cricket, there are often times where the requirements of a batsman are significantly different, while in first class cricket it’s rarely a bad idea to just score as many runs as possible, at whatever pace suits the player.

I wanted to have some players to compare him to, so I asked some of the South African journalists in the box who they felt was a streaky player.  The first suggestion was Morne van Wyk. A suggestion of another inconsistent player was Neil McKenzie.  I also wanted to look at a particularly consistent player, so I chose Stephen Fleming. The first thing that I did was to look at their 15 innings averages.  I also looked at 7 innings averages, but they seemed too random to be useful. Here are some graphs of each players 15 innings averages and cumulative averages:

We can see that Faf has had a remarkable run recently, and also why I was suggested to look at Morne Van Wyk. He went on some remarkable streaks of both good form and terrible form.

While McKenzie was obviously inconsistent, there weren't many extended patches of good or poor form.  Instead it looked like he was just an inconsistent batsman.

Fleming was remarkably consistent at the start of his career.  He was described as someone who averaged 40 by regularly scoring 40.  Later on in his career he started getting more big scores, but generally he remained a batsman who was fairly consistent.

We can also look at their consistency by looking at their 15-innings averages in a box and whisker graph.

We can see here that du Plessis has the largest range, by quite a margin, but that Morne van Wyk has a significantly larger interquartile range.  

After applying the randomisation technique, there are a couple of interesting results. The randomised results all came out with a very close approximation to a normal curve, so I’ve used mean and standard deviation to find the probability of a batsman being prone to high swings of form. A player who is always on a streak will have a value of 1, while a player who is completely consistent will have a value of 0.  Here are the 4 batsmen that we have the graphs of.

Stephen Fleming	0.135
Neil McKenzie	0.136
Morne van Wyk	0.984
Faf du Plessis	0.783

However, if we remove the start of du Plessis’ good run of form and re do the analysis, it comes out completely differently: 0.212  

In other words du Plessis was a quite consistent player until he started on his incredible run where he has averaged over 99 for the past 17 innings. It might be that he is finally having a hot spell, or it might be that he has actually just got a lot better.  This might actually be part of a new, consistently good career.

It will be interesting to find out. I hope for his sake that any time where he doesn’t score as many runs will be shorter than the times he spends at the top.