Duckworth-Lewis Method

Duckworth-Lewis method(D/L method) is a mathematical function defined to set and calculate the target score for the team batting second in One day international cricket matches. It is the most complex and irritating function for the audience who are watching cricket. People get confused with the target scores that are sometimes set for the team batting second.

The method was adopted by the International Cricket Council (ICC) in 1999 to address the problem of delayed one-day cricket matches for reasons of rain, poor light and floodlight failures although it has also been used in events that have been shortened due to crowd problem, sandstorms and even snowstorms.

Here is the calculator which can actually predict the target score. Set the numbers and try it out yourself.

Did you know:

The calculator above is based on the standard edition of the calculations which are accurate for first innings scores of up to 235, the resource table used is the most up-to-date as per the 2004 revision 2 Duckworth/lewis ball-by-ball table. The Professional edition of Duckworth-Lewis (aka CODA) would be used by officials for first innings scores greater than 235. Now if the game is reduced to 43 overs a side, the target for New-Zealand should be 280 in 43 overs.

There are a lot of questions which come to a Cricket lover’s mind while looking at the target scores and the final result. This should clarify a lot of them:

Q)“Team 1 make the excellent score of 350 in their 50 overs and Team 2 start their reply cautiously and reach 40/0 in 10 overs. The heavens now open (or the floodlights fail) and further play is ruled impossible. Under the Standard Edition of the D/L system Team 2 are declared the winners by 3 runs. They were clearly already falling behind the run rate they needed even allowing for the fact that they had all their wickets intact, so how can this result be justified?

A) The above represent the two worst-case scenarios for treatment by the Standard Edition of the D/L method. They could only give such extreme consequences with playing regulations that allow a minimum of 10 overs per side for the match to count. But a similar, though less exaggerated, injustice could still arise even with a minimum of 20 overs per side required. The Standard D/L method was devised so that anyone could perform the calculations with nothing more than the single table of resource percentages and a pocket calculator. This was regarded as an essential requirement for the method. It was considered that to be totally dependent on a computer would mean that the method could not be used universally, it would be vulnerable to computer failure and it would be more difficult to explain how the targets were calculated. The use of the simplifying single table of resource percentages meant that actual performance must necessarily be assumed to be proportional to average performance. In 95% of cases this assumption is valid, but the assumption breaks down when an actual performance is far above the average, as is the case in the scenarios of Q10 and Q11 and in the record-breaking match between South Africa and Australia (March 2006) in which South Africa scored 438/9 to beat Australia’s 434 in 50 overs. This problem has now been overcome by use of the Professional Edition and this has been in general use for most matches at the top level of the game, including ODIs, since early in 2004. It can only be operated by using a computer program. “

There are some great papers which explain the formulas and calculations around the Duckworth-Lewis method. Couple of them are:

A fair method for resetting the target in interrupted one-day cricket matches

A successful operational research intervention in one-day cricket

All you cricket nerds can now go ahead and predict the score before anybody else. Good Luck.