Sunday, September 28, 2008

Queensland v Kolkata

In a post some time back, Nestaquin told me that the Kolkata Knight Riders would be playing some games in Brisbane, and that I should go and report on what I see. Today they played the first of three double-headers against Queensland, and this gives me an easy way to end the neglect of this blog. The games were played at Allan Border Field, which is a lovely ground which doesn't have enough matches to warrant over-corporatisation — there's still a white picket fence, a hill, and trees.

The first Kolkata player I saw was Ajit Agarkar (at least I'm 90% sure it was him — I only saw him for a second or two), who was going for a jog as I was walking to the ground. But unfortunately he didn't play, as the coach John Buchanan brought his squad here to give the young guys some experience.

Boy do they need it. They batted first in the morning game. I had a pen and notepad, and decided to keep a tally of balls where the batsman was beaten (i.e., played and missed, miscued, hit on pad). I don't know of a good word to describe this, so I'll borrow the French football term occasion (which in football means a scoring opportunity). In 120 balls plus a few wides, there were 58 of these occasions, which makes one every other ball. The batsmen, mostly sub-first-class standard, were completely unable to cope with the pace and bounce of the quick bowlers. Then Chris Simpson came on to bowl some offies, and they weren't all that good against him either.

Sharma (not sure of his first name) gave up 12 occas on his way to 5 runs, and Patel gave up 10 on his way to 3 runs.

They crawled their way to 8/79 from their 20 overs. The only three batsmen to make double-figures were Michael Buchanan (John's son; he's been a fringe player for Queensland) with 16, their other opener Prashantha (I think that was his name — I didn't see a match programme, haven't seen a scorecard, and had to go by the ground announcer), who was steady-ish but slow and who scored 12 before getting out in the 8th over, and Adam Hollioake. I didn't even know he was still playing, but Cricinfo tells me that while he retired from first-class cricket in 2004, he kept playing T20's till 2007. Anyway, he looked pretty overweight, but he looked a class above most of his teammates.

There really wasn't much positive to take out of the batting. Even with only four fielders inside the circle, they were incapable of nudging singles. Symonds bowled two consecutive maidens with the field set deep!

I couldn't be bothered taking notes after that.

Their bowlers in the morning game were no better than the batsmen. Too short, too full, too much width, .... They might have been a bit unlucky, in the sense that every time the batsmen swung at the ball it found the middle of the bat, but it was still carnage. The Queensland openers whacked 80 runs in about 7 overs, and then they decided to keep playing, with a revised target of 180. They made it with about four overs to spare, with seven wickets in hand. Symonds failed, scoring just 2, skying a catch to long on with his first real swing of the bat.

I stuck around for the afternoon game, and I'm glad I did. Queensland batted first (shuffling their batting order), and this time the KKR bowlers stuck to a much better length. Short balls got to the head rather than the lower chest. And they had more luck, as batsmen started miscuing. Chaudry (I think) took three wickets. Queensland kept batting aggressively but lost wickets. Siddarth Kaul was one of the bowlers. Iqbal Abdullah bowled some left-arm orthodox darters and looked OK. I can't remember the others. They brought on a legspinner who struggled to find his length for a while, which meant that most of his spell was bad — when you only get four overs, there's not much time to get your rhythm. Queensland got to 8/96 after 12 and finished all out 129.

Michael Buchanan led the chase with 49 from 31. The batsmen at the other end were not so good, and when Buchanan was dismissed they were 4/80ish. They looked ready to collapse, but the lower-order kept hanging on, Hollioake again making double figures. I wasn't taking notes or tallying, but my impression was that they were much more solid, making contact with the ball and middling it a lot more often.

They needed 29 off the last two, and Daniel Doran bowled the nineteenth over (I think it was the nineteenth...). Doran must have good figures in grade cricket, because he keeps getting picked for Queensland, despite averaging over 70 with the ball in the last two years. Anyway, one of the KKR tailenders hit him for 16 runs in three balls (all straight hits I think), and they then needed 11 off the last over with one wicket in hand.

Grant Sullivan bowled it — he had looked sharp but lacked control and Buchanan had hit him around earlier. His first ball was short and gave too much width, and Kaul managed to get some bat on it and got a boundary to third man. 7 off 5. Dot ball. Third ball was good length, Kaul hits it over long off for 6, and momentarily thinks that he's won the match, but then realises that scores are tied. Field comes in. Dot ball. Dot ball. Last ball, defended to Andrew Symonds, they run, Symonds throws and misses, Kolkata win by one wicket.

The KKR guys were all happy with a win.

Sunday, September 07, 2008

Simulating one-day cricket and batting orders

I spent some of today reading through this paper (you'll probably need a University subscription to read that) by Swartz et al. It's called 'Optimal batting orders in one-day cricket', and it is useful because it gives a way of simulating one-day innings.

(The paper itself looks at the Indian batting order in the 2003 World Cup. The best they came up with went Dravid, Tendulkar, Ganguly, Sehwag, Mongia, Y Singh, Khan, Kaif, H Singh, Agarkar, Srinath. Their second-best lineup swapped Dravid and Ganguly, sent Kaif to 7. They reckon it would have done better by about 6 runs, on average, than their actual lineup for the World Cup final. Not many matches are won and lost by less than six runs, but I suppose you want to squeeze out every run you can. It's interesting that the simulations reckoned that Kaif was best left to come in and slog at the death. A full run of their simulations takes a long time — there are a lot of batting lineups to go through, even when you do clever tricks and make the search much smaller. But they say that it would be much quicker if you had only a limited number of options, such as during a match when you've lost a couple of wickets. Using a computer to find the optimal batting order based on the situation of the game meshes well with Rob Smyth's belief that batting orders in one-day should be fluid.)

The way they do it is to work out 'baseline' characteristics for each batsman in the team. That is, they get the probability that a batsman will play a dot ball, score a single, a 2, a 3, a 4, a 6, or get out. But they don't just take their overall career numbers, they take into account the match situation when they batted.

So, given the number of wickets fallen w, balls bowled b, Duckworth-Lewis percentage resources used R(w,b), what they actually did was fit parameters to a loglinear model that looks like this (the subscript k denotes what happened on the ball, so k = 0 is a dot, etc.; the subscript j refers to the jth batsman):

log(qjwbk) = μjk + αk*w/9 + βk*b/299 + θk*R(w,b)/100.

The μjk's give the baseline probabilities for each type of ball-result (dot, single, etc.) for each batsman at the start of the innings. (Well, not directly probabilities — the probabilities pjk are given by pjk = qjk / &Sigmak qjk.)

The other parameters (α, β, θ) describe how the probabilities change as the game situation changes. It is assumed that all batsmen change in the same way.

So that's all well and good. You throw the paramaters into the computer, generate a bunch of random numbers and you end up with 50 overs of simulated cricket. The results are pretty close to what real cricket scores are, at least at the team level. I tried running the same algorithm and one of the openers scored a double-century on the second run, so it's probably not perfect, but on the average it seems to do a good job. (I'm getting a slightly higher result for the team average — 253 against 250 — than the authors of the study did. Some minor bug in my code somewhere, I guess.)

Anyway, I think that this paper could be useful for me. What I want to do is see how to properly assess batting average and strike rate. So what I hope to do is get the relevant parameters for batsmen as a whole in the 2000's. Unfortunately, I don't have ball-by-ball ODI data, so I'm going to have to estimate it somehow. I've asked S Rajesh for the overall numbers (i.e., total dot balls, singles, 2's, etc.), and hopefully with some fiddling I'll get the weird loglinear parameters to match them.

The α, β, and θ parameters I'll leave unchanged. Hopefully India's batsmen from 1998 to 2003 (the period that the study looked at) are representative of how batsmen generally change over the course of an innings.

Then, once I've got a good simulator of an average batting lineup against average bowling, I'll be able to vary the parameters of one of the batsmen, tweaking average and strike rate (indirectly — I'll be tweaking probability of dismissal on each ball, and probability of each type of scoring shot). Then you see what effect this has on the average team score. So it'll be like the post below, only accurate. Hopefully.

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