West Indies vs Sri Lanka, 1st Test, 5th Day

I have resumed taking a more intense interest in cricket, and in the last couple of weeks have made a few comments over at Reddit, on the r/cricket reddit. (I did the same last summer, but without any lasting effect, so I do not promise to have resumed regular posts.)

The rest of this is a re-post of a slightly edited version of a post I made over there.

This all started when I checked CricViz' calculation of 'who was winning', against my own rather more nebulous 'Test Win Expectancy' model during the Mendis-Matthews partnership. Going by the match position, I thought Sri Lanka had grounds for optimism, even to the point that I suspected CricViz was doing something badly wrong. Having studied the data a bit more thoroughly in the light of subsequent events, I have to set my optimism for Sri Lanka's chances aside altogether. Basically, I had overrated the batting resources remaining to Sri Lanka. The actual target is not unattainable, on the face of it, but one wouldn't want to start from here.

In bald terms, Sri Lanka need two century partnerships between Mendis, Dickwella and a returned Chandimal. (A 50 from Dilruwan Perera would reduced the pressure on those three, but we're still talking about three big partnerships.)

The wickets of Kusal Perera and Silva fell at scores below par, while the Mendis-Matthews partnership was well above par. However, given the mammoth number of the target, Sri Lanka need multiple wickets to go well above par. Basically Mendis has already done his bit, and it is expecting too much of him to add substantially to his current score. (It could happen, of course, to the delight of Sri Lanka's supporters.)

So, now we are down to an uncertain Chandimal and Dickwella, who has a Test average of 33 and no centuries to his name. With those resources, it's hard to feel any optimism that 200 runs could be scored over the next two wickets. Of course, tails can wag, but the Sri Lankan tail-enders will be hard-pressed to make 77 runs between them, going by their averages, which make James Anderson look good.

As I suspected, and one can read on Reddit, Silva's wicket was crucial. My mistake was not to weight it heavily enough in subsequent posts. CricViz' 89% chance of a WIndies' victory doesn't look so far-fetched.

Pakistan in England, 2010, 4th Test.3

Hic sunt leones, a medieval cartographer might say of the parts unknown in which we find ourselves, win expectancy-wise.

Basically, England have about a 70 per cent chance of winning this match. But we've seen some violent swings in win expectancy today, and I'd be surprised if there aren't more during the rest of this match.

Pakistan n England 2010, 4th Test.2

Phew! You'd think Pakistan would be on top of the world after that first session. And you'd almost be right.

Unsurprisingly, breaking out the win expectancy calculator reveals that Pakistan's best chance of winning occurred after the fall of Morgan's wicket.

However, in between, surprisingly, the fall of Collingwood's wicket saw a big swing to England. When wickets fall fast, it's a case of what's sauce for the goose is sauce for the gander, as the pattern is set for the match. The side bowling second gets all the traditional advantages of the side bowling second, so wickets tumble even faster.

Pakistan's key wickets were those of Pietersen and Morgan. Even better for Pakistan, the current Trott-Prior partnership has seen England's win expectancy fall to its lowest level of the match, as the chance of a draw gradually rises.

At the moment, Pakistan have about a two-thirds chance of winning this match, and nearly a 9/10 chance of not losing it.

Pakistan in England 2010, 4th Test.1

The dismissal of Strauss had minimal impact on the Win Expectancy. England's chances of victory went down less that 0.1 per cent. Which is just another data point in my developing case that you don't actually need a big run total from your opening pair.

3rd Test, England vs Pakistan, 2010, Tea 3rd day

Well, actually, I looked at the win expectancy at the fall of Cook's wicket.

England should not take heart, although on a limited sample. Their chance of winning is poor, and a Pakistan victory seems the most likely outcome. England have a better chance of battling to a draw.

Of course, this is mercurial Pakistan, and if any team can upset the win expectancy apple cart, it is them.

2010 Nagpur Test, India vs South Africa (Win Expectancy)

I tuned into the play until lunch yesterday, and I managed to catch all the wicket-taking excitement.

I left off mostly talking about win expectancies. In this case, one needs to tinker with the model a little, since the situation is rather unique. Here's how significant the first wickets were.

After Prince was the victim of an umpiring mistake, South Africa had boosted their chances of winning by +.007. (There's a joke there, somewhere.)

Smith, however, 'popped out', as they say in baseball, to the wicketkeeper, and reduced the chance to 19 per cent, a loss of -15.

Kallis and Amlah set up 'shot' and hey-ho, took South Africa's chances of winning to 100 per cent. Except I don't believe that. The model has spit out a 'porky'. I'll come back and report after I've done a bit of figuring. I think I know how to handle this.

Meanwhile, readers with longer memories might like to recall this match.

Kennington Oval, Ashes 2009, #4

England fans were whooping up a storm as Australian wickets fell before the spin of Swann and the pace of Broad. For once, it appeared, the English brains trust had out-thought the Australians'. Then, of course, one-two-three, wickets fell as England attempted to gain more ground on a strong Australian batting line-up that could be expected to crank out 400 runs.

At close of play last night, England's Win Expectancy stood at something around 32%, which isn't any better than what you'd get at the start of a Test. However, Strauss and Trott batted away the morning session, until Strauss's wicket fell just before lunch.

The Win Expectancy model would surprisingly suggest that England's chances of winning continue to dwindle. Go figure. One problem with my model is that there aren't many examples of a match like this Test.

CricInfo's Hawk-Eye (linked via the scorecard there) sees an 80 per cent chance of an England win. I can't help but think they are underestimating Australia's batsmen.

Edgbaston Win Expectancy Shifts

The Third Test between England and Australia produced, apart from this curiosity, some big shifts in win expectancy. I've pulled out the three biggest positive shifts, in terms of the side batting, and the three biggest negative ones. Reverse the polarity if you want to look at it in terms of bowling.

BIG Plus
Watson-Ponting, 41 runs for the 2nd wicket in AUS1 (+.218)
Watson-Hussey, 85 runs for the 3rd wicket in AUS2 (+.197)
Cook-Bopara, 58 runs for the 2nd wicket in ENG1 (+.171)

BIG Minus
Hussey, 0, in AUS1 (-.287)
Collingwood, 13, in ENG1 (-.188)
Ponting, 5, in AUS2 (-.178)

Honourable mention has to go to Cook, 0, in ENG1, which was worth -.176.

It's worth noting that for wickets or stands to count, they really need to come in pairs. It's no good piling on 100 runs and follow it with a pittance. Nor is taking a top batsman's wicket for a low score worth much if you don't break up the next partnership pretty quickly. You can let the wicket after that go for a bit, though. Anapestic metre, if you're of a poetic mind.

Are you surprised that the massive Clarke-North stand in the Australian second innings didn't appear? Probably not, as it was too late in the match to affect anything other than their averages. It actually did produce a positive effect, but I just wonder if the Australians should have cut it short when it was around a hundred and gone for a win. You never know.

Passing Observation

I am currently doing some win expectancy analysis of the Third Test in the Ashes series, and I noticed a curious fact. It seems that Australia's 7th and 8th wicket stands, which between them added a single run, actually improved their chances of winning. Is there some kind of cricket Moneyball-style market inefficiency we can take advantage of here? 'Hey, Johnson, throw your wicket away so we can win the match.'

The only explanation I can come up with for that, without examining all the Test scorecards, is that it suggests that the pitch or conditions favour the bowlers to such an extent that the side in can expect to take a lot of wickets quickly once the innings finish. If anyone has a better hypothesis, I'd be interested to hear it.

As soon as I finish the analysis, which I hope is later today, I'll post some thoughts about the drawn Test.