I DECLARE, THAT'S NOT CRICKET!

Cricket wouldn't be cricket, and Richie Benaud wouldn't have much to say, without statistics.

Batting averages, centuries, fastest centuries, and the number of Australian twelfth men who have
never played a test (15) all get a statistical showing on the cricket web site, Baggy Green.

But bare numbers aren't the only role for maths in cricket. Mathematicians have now developed a
program that tells test cricketers when to declare and when to bat on.

Dr Elliot Tonkes, a lecturer at the University of Queensland, is presenting his yet-to-be-published
paper on answering the declaration dilemma at this week's International Congress on Industrial and Applied Mathematics in Sydney.

Tonkes wrote the paper - and related computer program - after doing mathematically similar work on the financial derivative markets. Both use models to help decide when to exercise an opportunity. In derivatives, it is when to sell a contract for the future supply of something and in test cricket, it is when to declare an innings.

The fundamental of both is "maximising your expected pay off," he said. In cricket, that pay off is a victory.

"If there are three balls to go and they've got ten wickets in hand but [are] a long way behind, it's
going to be a draw, but it gets more iffy that that," Tonkes said.

The program takes in variables such as balls to go, runs scored, wickets remaining and the
possibilities from the next ball (0-6 runs, a wicket or a declaration) to advise the captain of the best strategic option. "It's all about probabilities," he said.

His program wasn't developed for any particular team - the Australian team doesn't have it - and its current parameters don't account for unorthodox options, like the shameful-yet-effective under-arm bowl.

Tonkes' motivation to develop it was simply interest. "The unintuitive things are the great ones to
discover, but you can also solve problems, make things better - make cricket teams better," he said.

©The Sydney Morning Herald
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