|Author: Prateek Sharma 10 May 2012 Member Level: Silver Points : 15 (Rs 10) Voting Score: 0|
The Duckworth/Lewis (D/L) method of target resetting in one-day cricket was first used early in 1997 and has since spread to most of the cricketing world. On 1 Sept 2001 the method became the official 'rain-rule' in use in all one-day competitions in ICC full, associate and affiliate member countries.
The method is based on the concept that a match starts with both teams possessing the same resources to build their innings. They have a fixed number of overs to receive, usually 50 in international matches, and they have ten wickets to lose.
As the innings progresses these two resources are gradually used up and a single table of figures gives the percentages of the run scoring resources of the innings that remain for all possible combinations of overs left and wickets lost. The table has been constructed from a detailed study of the scorecards from many hundreds of one-day matches, mainly internationals, played over recent years.
If an innings is interrupted and has to be shortened, the table is used to find out what percentage of the resources is lost.
Any shortening of the match after it has started upsets the balance of resources and a revised target is necessary to compensate the team that has suffered the more. This is the case even if the two teams both end up with the same number of overs to receive.
The target adjustment is based on the relative run scoring resources available to the two sides after the resources lost by each team have been taken into account.
The table reflects the fact that the resources lost by a loss of a certain number of overs depend on:-
How many overs remained, and
How many wickets were down at the time.
For instance, a loss of overs near the end of an innings, especially when there are plenty of wickets still in hand, is usually a far greater loss of resource than the same loss of overs at the beginning of an innings.
How it works
Suppose the team batting first (Team 1) have completed their innings and an interruption occurs during the second innings. The team batting second (Team 2) will then have less resources for their innings than Team 1. In this case Team 2 will be set a reduced target based on the smaller amount of resources they had for their innings compared with Team 1.
But if an interruption occurs during Team 1's innings, it often happens that Team 2 end up with more resources for their innings than Team 1 have had and in this case their target is revised upwards to compensate Team 1 for the way they were more disadvantaged by the timing of the stoppage.
This is best understood by considering the case where Team 1's innings is curtailed after 40 of an intended 50 overs and Team 2 have just time to face the same 40 overs. Team 1 had been pacing their innings to last 50 overs and provided they had wickets in hand might have expected to have made 60 or 70 runs from the final 10 overs.
Team 2, on the other hand, knew they had only 40 overs to face from the moment they started their innings and were able to take greater risks to achieve a higher scoring rate right from the start. On average a team only make about 20 - 25 fewer runs from a 40-over innings than they make from a 50-over innings.
Provided that the minimum number of overs have been faced by each side, if a match has to be terminated before a result has been obtained, this is decided by comparing Team 2's score at the termination with the 'par score' for their target. The par score is calculated in the same way as a revised target and is the score that Team 2 would have to have exceeded to win if the game were abandoned at that point. Like a revised target it depends on how many overs remain and wickets are lost.
If Team 2's innings has to be abandoned, Team 2 will win if they are ahead of the par score, by the amount that they are ahead. If they are behind par then Team 1 win by the corresponding amount. If they are equal to par, the match is tied.
During the progress of Team 2's innings, and regardless of whether or not rain is threatening, the par score provides a useful guide as to how Team 2 are performing relative to their target. This information is sometimes displayed on scoreboards, usually as the par score for the end of the over in progress.
The revised target
Match regulations dictate that a tied match will always be possible even when a revised target has been set. The revised target is the minimum number of runs that Team 2 require to win the game. The calculated score to beat is rounded down as necessary (i.e. ignore any figures after the decimal point) to give the score needed for a tie. The target is one more run than this.
The D/L table
The D/L table as supplied to the scorers fits on a single sheet and covers every over from 50 down to 1 and each number of wickets lost from 0 to 9. A longer version of the table covering every individual ball is also supplied for dealing with cases where the stoppage occurs mid-over.
Below is an abbreviated version of the table for use with the examples following. The figures given are the resource percentages remaining relative to those for a full 50-over innings.
Resource Percentage Remaining...
Overs left wkts lost
0 2 5 8
50 100.0 85.1 49.0 11.9
40 89.3 77.8 47.6 11.9
30 75.1 67.3 44.7 11.9
20 56.6 52.4 38.6 11.9
10 32.1 30.8 26.1 11.4
5 17.2 16.8 15.4 9.40