Sunday, 22 August 2010

Alastair Cook, Stay or Go?

Alastair Cook is 25 years old, a left-handed bat, and bats in the first, second or third positions in the batting order during his career.

I took all batsmen who meet those qualifications in what might be called the 'Bangladesh Era' of Test cricket (since 2000), plus all England batsmen who also meet those qualifications, with a minimum of ten innings of batting. I then compared their Innings Average, their Bowling Overs per Innings and the Standard Deviation of their innings' scores. For those who think a hundred against Bangladesh might only be worth, say 80 runs against a better Test side, I also calculated the Innings Average by adjusting the value of Cook's runs downwards by 10 per cent, 20 per cent, 25 per cent and 33.3 per cent. (When you get to 50 per cent, you may as well exclude Bangladesh altogether, so I did that, too.) I'll rank them by Innings Average.
Player           InnAve   BO/I     StDev   Dates
Cook (-10%) 48.02
Alastair Cook 45.44 13.70 49.87 2009/10
Cook (-20%) 40.99
Kumar Sangakkara 40.40 13.00 29.39 2002/03
Cook (-25%) 39.88
Cook (no BAN) 37.91 42.96
Cook (-33.3%) 37.87
David Gower 37.62 13.63 30.02 1982/83
Wavell Hinds 36.70 11.50 34.09 2002
Salman Butt 34.80 12.26 30.59 2009/10
Graeme Smith 32.24 8.32 26.60 2006/07
Mark Butcher 30.87 13.70 33.27 1998
Sadagoppan Ramesh27.58 10.84 22.29 2000/01

The idea of dropping Cook because of his current poor run of form overlooks the fact that he isn't actually having a bad year. In fact, in this set of batsmen he is having the best age-25 year of them all, with the best Innings Average and tied for the best BO/I numbers with Mark Butcher's 1998.

The only warning sign is the very high standard deviation in Cook's innings' scores. As you can see, the better players in this list have much narrower deviations. As in the case of Ramesh, however, it is possible to have too narrow a deviation. My studies of the significance of standard deviations are still rudimentary. It does seem that there is a sweet spot of these in which class batters tend to maintain, and players who fall either side of this are flattering to deceive if they seem any good.

So, if there's an obvious alternative to Cook, then it might be worth including him in any Ashes squad. But Cook still seems to deserve his place, as far as the statistics can show us.

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