Sunday, March 15, 2009

Batted ball speed

Hey look, I have this thing called a blog, maybe I should update it.

I should update my profile – I'm no longer a student (sort of, my Masters thesis is under assessment), having got out of my PhD and started a 9-5 job, which is in geostatistics, if anyone is wondering.

I've been very slack with cricket stats lately, with work and chess taking up more of my time. Anyway, this is a long and interesting discussion about a baseball hitting a baseball bat. The very counter-intuitive result is that the batted ball speed doesn't depend on the grip, as long as the ball hits the "meat" of the bat. The same is true for cricket (this page gives a few physicsy aspects of cricket). All that matters for batted ball speed is the speed of the bat at impact.

On a different topic, I have been thinking about putting my cricket database online. It wouldn't be pretty, and any professional coders out there may be horrified at my code, but there are enough of you out there with good ideas that I think it would be worthwhile. In the long term, I would like there to be a cricket equivalent of Retrosheet, which now has over 50 years' worth of play-by-play data for Major League Baseball.

I'm sort of thinking out loud on this at the moment. My database uses CricketArchive player and match ID's, so if they changed their numbering system (which they did a few years ago), that'd screw things up. I might exchange emails with them and see what comes out of it.

Feel free to share your thoughts on this.

I'll tell you one thing.

You could make a fortune betting on cricket!

Great blog, good to see a new post.

I have a question which you may be able to help me with. During a 90 over day in a test, is there a particular ball which gets a higher proportion of wickets? i.e first ball of the day, last ball of the day, last ball before tea.

I have always wondered and suspected it is the first ball of the day.
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It was great to see that you are thinking about opening up your cricket database. It will definitely revolutionize cricket stats. It would be even better if Cricinfo can put up its 3D data online or give APIs to access their data like MLB does with it pitch by pitch data.

My biggest grouse is that we don't have adjusted stats in cricket like OPS+ in baseball available online. There is a paper by Lewis (Duckworth-Lewis fame) on adjusting numbers in ODI, "Towards fairer measures of player performance in one-day cricket". The idea is similar expected runs matrix in Baseball based on bases occupied and outs.

It pains me that commentators routinely profess ignorance of D/L rules. Well it is ok not to understand every detail but at least they can understand the essence of rules and explain it. I remember watching India v England at Bangalore in Nov 2008 on TV. The match was interrupted by rain in the first innings. There was rain when India had finished playing 14 out of the possible 50 overs. After another rain interruption, the match was finally reduced to 22 overs. The commentators could not understand why score was revised upwards when England started chasing. They could not understand the simple logic that the Indians played the first 14 overs thinking it was a 50 over match. But England knows right from the beginning it is a 22 over game. D/L adjusted the target to make it fairer for India who batted first and played the first 14 overs without the knowledge that it was going to be a 22 overs game. Times of India reporter Satish Viswanathan called D/L rules strange when the target was revised upwards. I hope it won't take long time like baseball for new age statistics to be accepted in mainstream.

The good thing is that we can borrow ideas not only from the Baseball Sabermetric group but also from the fledgling Basketball APBRmetrics group. The one stat which can be directly applied from Basketball is the % blocked shots of an offensive player. This can be translated in cricket to % of shots that a player hit directly to a fielder inside the ring.
David, great to see you're thinking about opening up your database - do it! I'm just starting to do some analysis of my own, and invariably, I spend the most time trying to get the relevant data, and parse it into a form suitable for analysis.

@AR: An API for Statsguru would be fantastic. Do you have a link to the Lewis paper?
By the way, Gus, I suspect it's the last ball of one of the sessions, for a simple reason. If a wicket falls on anywhere in what would be the last 1-2 overs of the session, the break is usually taken right then. So I'd say it's ~5-10x more likely to be the last ball of a session, because the bowler essentially has several balls with which to take a wicket that ends the session. I'd be interested to see actual numbers on this.

Unfortunately that paper is not available freely over the web. You have to check it out at the library. Searching for that 2005 paper led me another paper by Lewis in 2008.
Just for reference, the two papers are

(1) Towards fairer measures of player performance in one-day cricket

AJ Lewis - Journal of the Operational Research Society, 2005

(2) Extending the range of player-performance measures in one-day cricket

AJ Lewis - Journal of the Operational Research Society, 2008
Thanks AR! I'll try to find them.
I am also frustrated at the lack of an easy-to-use cricket database as I have a lot of ideas that I would like to implement that simply take too much time with what I have. The baseball guys have it great, except that there are like 100 times more of them, so all the easy stuff has been done already.
I have started a new blog, which is a lot like this one, but probably worse. For some of the posts I see there are similar posts here, which I didn't know about. In any case you might find it interesting and I would appreciate it if you could add my blog to your blogroll.
Ron, that's great! Will have a closer read later.

You'll also want to familiarise yourself with some of Charles Davis's work, though he spends a lot of his time chasing up records and historical data rather than doing detailed analysis (I don't mean that as a slight against him - I am very glad that someone is spending the time laboriously gathering balls-faced data on old Test matches).

Davis wrote about how nightwatchmen are inneffective in his 2000 book The Best of the Best, which is unfortunately out of print (though you can see that chapter in the "longer articles" section of his website). He also noted the lack of influence of the toss in that book.
Nice post, enjoyed reading it
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