Thursday, January 12, 2012

Summer Fun

It is the summer holidays, a time at which one’s thoughts move from idiotic economic policy and commentary, to enjoying the annual ritual of getting the garden under control while listening to live cricket.

So naturally, blogging has to go into summer mode as well. The cricinfo blog, of course, is locked permanently in summer mode. A recent post there concerns the importance of controlling for pitch quality in any statistical analysis of performance. Essentially, we are dealing with the econometric issue of misspecification in which independent variables are correlated with an error term if we cannot include a variable for pitch quality in analysis.

The author of this blog post proposes a method for using information from the match to control for pitch quality, by combining the runs per wicket and balls per wicket in the match. This looks like a useful first step but I see two limitations: First, the method for combining these two statistics is ad hoc rather than resting on foundations from a theoretical model of the processes driving outcomes; and second, the method seems to overreach, by ascribing all of the variance in scores between matches to the pitch quality and none to relative performance, when in reality performance and conditions both contribute to the observed variance in scores across matches.

My former student, Scott Brooker, and I have recently put out a paper drawn from Scott’s Ph.D. thesis, in which we propose a theory-based method for estimating from historical data the pitch quality in ODI matches. It will be of interest only to cricket loving stats geeks, but if you are a member of that fairly large community, do check out our paper here. We will be drip feeding more work from this research agenda into working papers over the next few months, including a paper on how incorporating pitch information can lead to improved rules for adjusting targets in rain-affected matches.

Postscript: Needless to say, my co-blogger at Offsetting has even less interest in cricket than he does in rugby, but rest assured that is a deficit that his colleagues have been trying desperately to correct over several years!


  1. I deeply dislike cricket, but there was a fascinating interview to Brett Sipthorpe (head groundskeeper at the Basin Reserve) in Radio NZ I was really interested by the level of care required to prepare the pitch.

  2. I can understand why many folk, your co-blogger included, have difficulties with cricket, especially the longer form of the game. Personally I love it, it is easily my favourite sport. I love the quirks, the intricacies, and the swings in fortune that can occur during a test match. To some the idea that you can play a game for 5 days and still not end up with a result makes no sense, but there are times when the last session on day 5 can be absolutely gripping as the tail-enders struggle to retain wickets against a fired-up bowling attack eager to break through and claim victory. The subtle field changes, the grace of a fluid drive to the long on boundary, the battle between an in-form batsman and a wily bowler - it is heady stuff indeed.

    I am a bit of a traditionalist, and lament the arrival of 20/20. I appreciate the attractiveness to sports administrators of the income to be made from 20/20, but I do feel it is a threat to the long-term viability of test cricket. There is no Duckworth/Lewis in test cricket, and varying pitch conditions are part of the rich tapestry of the game, are to be embraced and planned for, and good captains incorporate changing pitch and weather conditions into their game strategy. At times it can be hard work being a NZ cricket fan, our team is not the most consistent performer, but they are none-the-less the best team we can field and I will always support them and wish them success, even if they can't always deliver for us.

    Keep chipping away at Eric, maybe one day he can put aside his North American cultural prejudices and learn to appreciate the grace and beauty of our summer game.

  3. I went to a cricket match once; it was fun. NZ vs West Indes; NZ won after a nutty Vittori catch on what otherwise would have been a Windy 6. But the opportunity costs for a whole-day game are, well, a whole day.

  4. I agree that there is a time cost to going to a game, which is one of the reasons why I haven't attended a match for a few years now, but the TV is tuned to NZ cricket matches when they are on at a reasonable hour and I'm at home. Otherwise it is live-scoring on the interweb if I'm at work, or some loss of productivity the next day when I catch up with the previous day's play :)

  5. Eric. The catch was by Nathan Astle and a day at the cricket is an opportunity gain!!

  6. @Lats. I agree with you about 20/20. I used to think the same about the ODI format but am now a convert to it for the reason that strategic nous plays a larger role in the ODI format than tests or 20/20. I continue to insist, however, that coloured clothing in cricket ranks equally with the pyramid at the Louvre as the greatest aesthetic crimes of the 20th century.

    @Eric. Shame on you for forgetting who took that catch. Google "Astle catch YouTube" to refresh your memory!

  7. But there is a player called Vittori, and he was likely on the field at the time, right?

    I'd have thought I'd get mild kudos for remembering that some kind of impressive catch happened. If I'd remembered it was Astle, y'all woulda rubbed me for mucking up how many outs the West Indies had at the time, or the time of the catch... no pleasing you fanatics.

    Klaatu baratta (harumphcough) is good enough....

  8. And autocorrect turns ribbed into rubbed. I give up.

  9. @Paul That explains it, I was wracking my brain to try to remember and outrageous catch by Vettori on the boundary. I remember the Astle catch, was quite something. He's a sad loss to NZ cricket, he could probably still earn a place in the 1st 11 today. He definitely retired before his time.

    @Seamus I haven't seen the pyramid in the flesh, so to speak, so will reserve judgement until I can appreciate it in its natural environment. Photos on the net don't necessarily do it justice. On coloured clothing, however, I see it as part of the marketing strategy to attract punters to the shorter version of the game. I don't particularly dislike it, but I treat it with much the same disregard as I do the continual changes to Super Rugby jerseys, a fairly transparent attempt to grab cash from fans who feel the need to purchase their preferred teams strip and publicly display their allegiance.

  10. And speaking of great catches, here's one from HRV cup action the other day...

  11. Lads, have you caught another of my former professor's papers, Greame Guthrie at VUW on an alternative to Duckworth-Lewis?

  12. @ Robbie. Yes, we know the Carter-Guthrie paper. They had a fairly small database. When you apply their method to our much larger set of games, we show that CG is a big improvement on DL, and that we can get another big improvement by using our measures of pitch quality. If you apply the method to 20-20, the advantage over DL becomes even bigger.


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