Nightwatchmen and protection, first pass
Russell Degnan

Responding to Ponting's use of a nightwatchman in Perth, Steve James made an interesting pointless that their value mostly derives from not having to start again the following day. Which raises the interesting question of how large a problem starting is. It is well established that batsmen start very badly - on nought - and then gradually improve up until the seventies, with an odd but not unexpected jump after passing 100. Compared with starting from an overnight score, and using the top 5 as comparison - the figures for the top order are broadly similar - we can see nearly identical graphs right through the first 100 runs after restarting, notwithstanding some random variation.

Except one aspect, which can be seen by zooming in on the first twenty scored. Batsman on a duck are significantly more likely to get out. Yet there would appear to be no good reason for this, except anxiety, as other than on nought batsman set themselves much the same?

By calculating the difference between the average once a batsman passes 20 - around 43 - with the runs lost by being dismissed early we obtain a difference of 6.2 runs for a batsman beginning his innings and 5.2 for one starting again the next morning. This apparent advantage is offset by a loss of 0.7 runs for a number 8 or 9 batsman, but nevertheless ought to gain some advantage for the following batsman. That it apparently doesn't is the why this will be a series, not just one post.

And to further muddy the waters on the first question. The probability of being dismissed on an overnight score shows no such bias for nought with batsmen on one run just as vulnerable. Although again, there are strange patterns of vulnerability when starting from a low score or a middling one that don't appear random.

That is two mysteries then. Why do batsmen play themselves in an identical manner when regardless of time spent at the crease the night before, except for the first run. And why are there large variations in dismissal rates at various points after an overnight score?

Idle Summers 13th December, 2012 23:02:13   [#]