Thursday, May 01, 2008

Maximising runs or wins

In a post at 99.94, I took the comments thread off on a long tangent that was only just related to the original post.

It got me thinking about batting strategies (at a conceptual level) in limited-overs cricket. Batting second, it's simple: choose the strategy to maximise your chance of reaching the target. Every team does this instinctively — chasing 350, they go for broke, and often end up losing by a lot.

Batting first, I'm not sure what the optimal strategy is. Instinctively, I at first thought that you should choose the strategy to maximise the expected number of runs that you score. But scoring runs isn't actually the end goal — it's winning the game. And increasing the average number of runs you score won't always improve your win/loss ratio.

To take an extreme example, suppose you're a really bad team like Bangladesh, up against a team like Australia. Whenever Bangladesh bats first, they choose the run-maximising strategy. The results might be a bell curve centred around 180. So a lot of scores around 170-190, a few past 200, a few below 160, etc.

Now Australia has no problem chasing any of those. Australia's only going to have problems when the target's up over 250. So while the Bangladeshi averages will be best-served by going with the run-maximising strategy, they may end up losing every game.

On the other hand, if they play more aggressively, then sometimes their batsmen will have a bit of luck and they'll end up with a big score. In their long series of matches with Australia, they'll have loads of heavy defeats, after making scores like 120 and 150 and so on, but every now and then, they'll make 250 and have a chance at winning. So their averages will suffer, but their win/loss ratio will improve.

It'd be a public relations disaster, of course — all those thrashings.

If you've got two more evenly-matched sides, choosing the win-maximising strategy when batting first becomes problematic. Maybe you've studied the opposition's batting and concluded that you're best-off aiming for 270+. But maybe the pitch is not so good, and you don't know how to adjust that 270 score. You'll probably go back to a run-maximising strategy.

Nevertheless, I think with a very careful analysis, there's scope for improving win/loss ratios. I think it's most applicable in T20, because it's so short. If you bat first and lose early wickets, what do you do? Go for broke (hoping for 140 but probably getting 90), perhaps, rather than slowly batting out the overs (and getting 120)? It'll probably need a few years of IPL before we have enough data to say.

On an unrelated topic, the latest post chez Z-Score has a teaser question: What is the highest Test partnership for a pair who only batted once together in Tests? The hints are that they aren't Australian, and that the partnership is higher than 320. For those who don't want to search for it themselves, feed this into ROT13:


G'Day Dave. Australia have a fluid strategy when batting first in 50 over cricket.

Put simply, they are prepared to lose two sometimes three wickets in the first fifteen overs. Players like Gilchrist, Hayden, Ponting and MWaugh before them are given license to score as quickly as they are able when the field is up.

This allows the top 3 or 4 to "set the platform" as we say Downunder.

After this period the middle order then chop the innings up into 5 over blocks setting targets that often increase as the innings develops.

If none or one wicket is down at 15 you will see them up the tempo markedly until one of the batters falls.

The same applies throughout the innings. When each partnership begins they set the clock back to zero and try to increase the run rate in four or five over blocks until they are at the their limit.

Around the 40 over mark they set a final target and usually one that seems just out reach especially if 6 or more wickets are in hand.

Having a deep classy batting order that is experienced and can think on their feet has probably allowed Australia to almost perfect the art of batting first in ODIs.

Three World Cups in a row and 20 odd wins straight in this most important of tournaments shows that they have a strategy that is highly effective.

Australia turned up at the last T20 Championships in South Africa not knowing what to expect and even though they made the semis they really had no strategy.

In their last few matches they have developed a similar yet shortened version of the 50 over strategy.

They trounced both New Zealand and India last season and I expect at next year's tournament in England they will be difficult to beat now they have had time to understand the T20 game.
Thanks for that Nesta - interesting stuff.

I don't think I'd put Australia's semi-final loss in the T20 to a lack of batting-first strategy, since they lost chasing. I'd put it down to the T20 dice. Australia can't always win, especially in the really short game.

I'll have a post up on the other stuff you talked about shortly.
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