The Bradman Class and Sabermetrics

My link in yesterday's blog, which was to a discussion on the validity of sabermetric methods for cricket, was itself generated by the publication of this paper in The Journal of Quantitative Analysis in Sports.

The authors propose a new method of evaluating Test batsmen, which tries to incorporate the consistency of a batsman's innings. Someone like Alistair Cook has a high average this year, but it's a consequence of a couple of big innings, rather than consistency. His median score is quite low. The question the paper's authors don't address, however, is whether a consistent batsman is more likely to produce Test match wins. What they do look at is the relative importance of a batsman's average to that of his team-mates, but this isn't the same thing.

This is where most of what passes for sabermetric research in cricket misses the point. Ranking batsmen is jolly good fun for a discussion down the pub. What I want to know, however, is the relationship between runs and wins.

And that's what I still regard as my key discovery: it is more important to stop your wicket from being taken than to score masses of runs. This means it is more important to have bowlers who take wickets than to have batsmen who score runs. The secret to success in Test cricket is the right balance between how quickly you take wickets, and how slowly you lose them. The first building block in this is to find bowlers, not batsmen. And that raises an interesting question about the relationship between bowlers' overuse and injuries or declines in effectiveness.

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.

Comments on Rankings

Although I claim to have the oldest cricket website on the web that uses sabermetric methods, Charles Davis can also claim to have used sabermetric methods, and his web site was around before mine. He wrote a little piece for the Melbourne Age which is worth a read, although the rankings he advertises are not apparent on the web site. Check out his blog, which is in my links, where the rankings might appear. (Haven't looked myself.)

How Good Might JP Duminy Be?

Duminy's heroic stand for 166 in Melbourne yesterday, following his earlier heroics in Perth, had me wondering who might have amassed between 50 and 200 runs in a Test match debut. Is Duminy laying down a marker to be a great batsman?

Now, I'm not interested in the score, because my explorations of what wins cricket matches suggests to me that the kind of batsmen one wants are those who are consistently hard to get out, not necessarily 'Sydney or the Bush' merchants who rack up centuries now and then. Bowlers who take wickets at a high rate and batsmen who don't get out are the players who keep a side in the match. So instead of ranking people by score, I used CricInfo StatsGuru to rank them by balls faced. Note that I was only interested in debutants whose side batted second, in order to reduce the consideration set to as close a parallel as possible to Duminy.

Focusing on all those players within one standard deviation of Duminy's strike rate, we get a broad mix of talent, ranging from Tapash Baisya of Bangladesh, a bowler whose innings average doesn't even top ten*, to the late Taslim Arif, who managed to average just over 50 in a mere six Test matches. (A wicketkeeper, he gave way to Wasim Bari. You'd think they'd still have wanted his bat in the order somewhere.) Meanwhile, there's a couple of significant batsmen for whom we don't have complete Balls Faced statistics, in Lloyd and Gavaskar, and a couple of interesting might-have-beens in Amaranth and Baichan.

Overall, the standard deviation shortlist averages 34.60. The median belongs to Chandika Hathurusinga, at 28.95. It's too early to say more than Duminy has the potential to be a useful batsmen, and with a chance at being an all-time great. But it's most likely that he'll do well for a few years, until someone better comes along.

*Makes you wonder if they've heard of Babe Ruth, converted from pitcher to Hall of Fame slugger, in Bangladesh.