T20 World Match 2014 England V New Zealand Group 1 – A failure of the Duckworth and Lewis method?
The group match between England and New Zealand saw England score 172 for 6 in their allotted twenty overs. New Zealand responded with 52 for a wicket in 5.2 overs when play had to be suspended due to thunderstorms and rain. New Zealand was declared the winner using the D&L method.
These are the reasons why NZ should not have been declared the winner.
Of the 379 T20s played up to this match, the team playing second has chased 173 or more just 13 times,
New Zealand has chased a target of 172 or more just once. But the opposition at the time was a weaker team from Zimbabwe. (NZ vs Zimbabwe in Hamilton on February 14, 2012)
New Zealand successfully chased a target of 169 against SA, a stronger team. (NZ vs SA in East London December 23, 2012).
So based on historical data, the chance that a team can chase 173 is 13/379 is 3.43%. Which implies that NZ would have lost this game 96.57% of the time.
Following New Zealand’s own record they have played around 72 T20’s of which they have won a game chasing over 172 just one ounce. But that was against a weaker team, and indeed, I never really chased a target over 172.
Therefore, the D&L method awarded the match in favor of NZ when the original result would have been a loss in 96-97% of cases.
The flaws of the D&L method are:
a.) The Method does not take into account the probability or chance that a team would have won or lost the original game, had it not been interrupted by rain. Here the original result could have been altered by the D&L method.
If one does not consider historical data and uses data that is related only to scoring patterns during an inning, then,
b.) New Zealand at 52 for 1 after 5.2 overs could have lost wickets due to the pressure of chasing a high goal. After 5.2 overs, it is not possible to predict the outcome of the actual game with 100% accuracy. If there were 172 runs to score and if NZ had been 140 for 1 after 15 overs and it had rained then we could be sure that NZ would have won 90% of the time. So after 5.2 overs there is only less than 10% chance that the prediction itself will be correct.
The D&L method should not be used in all cases. It should be used only when the probability that your prediction is correct and accurate is high. In the case of this match, the progress of the game after 5.2 overs to 20 was not guaranteed and would surely result in a win for NZ.
The D&L method should not change an easily predictable ‘original result’, as in this case England would have won 97% of the time a target of 172 is set, but still declared ‘lost’.