Unlike several other sports, where rain doesn’t affect play, cricket is largely influenced by the weather. When it starts pouring, the entire state of the match may change. One of the most prominent examples is the 1992 World Cup semifinal between South Africa and England. South Africa needed 22 off 13 balls when rain interrupted play. Once the play was resumed, the revised target read as ’22 off 1 ball’. This impossible equation was only the beginning of several heartbreaks which were to follow for the South African cricket team in World Cups. However, the method which determined ’22 off 1 ball’ was not the DLS method. It was the Most Productive Overs method. In order to fill the loophole of this method, the Duckworth-Lewis method was introduced (Duckworth-Lewis-Stern, since 2014).
The Duckworth-Lewis-Stern method has always been under scrutiny for the incredulous scores which it sets. However, it is better than its predecessors in terms of being just. The DLS method accounts for in which innings play has been interrupted, number of overs remaining when play has been interrupted, and the number of wickets remaining.
1. Whether play is interrupted in the first innings or second innings: If the team batting (Team A) first has played 18 overs when rain interrupts play, the overs are reduced from 50 overs to 22 overs per side (say). Play resumes, and now Team A has 4 overs remaining to bat. Say, after 22 overs, Team A is 162/5. Naturally, the target for Team B should be 163 runs, but that won’t be the case when DLS method is applied. This is because until the 18 overs faced by Team A, the match was supposedly of 50 overs, and Team A was batting accordingly (teams usually play safe in the middle overs, and try to score heavy in the last 10 overs). Therefore, in order to nullify the advantage which Team B may have (knowing that their innings would be of 22 overs and not 50), the DLS method sets a score higher than that scored by Team A in 22 overs. If play is interrupted in second innings,
2. Number of overs and wickets remaining: Wickets and overs are collectively termed as ‘resources’. DLS method utilizes the following chart (or something vaguely similar) to determine what percentage of resources a team has:
Team B’s par score= Team A’s score *(Team B’s resources)/(Team A’s resources).
Let’s use this to calculate the target of Team B.
Summarizing the example undertaken:
1. Team A bats first when play is said to be of 50 overs.
2. Rain interrupts play when 18 overs have been bowled, reducing total overs to be of 22 overs.
3. Team A bats the remaining 4 overs. At the end of 22 overs, Team A is 162/5.
4. Team B at the start of the second innings, is aware that it has to bat for only 22 overs instead of 50 (unlike Team A).
5. DLS method is used to compensate for Team B’s advantage by setting a higher target (not the usual 163 runs) as follows:
Team B’s target= Team A’s total *(Resources of Team B)/(Team A’s resources).
Team A’s total=162 runs.
Resources of Team B (22 overs, 10 wickets at the start of second innings): 60.7%.
Resources of Team A (22 overs, 5 wickets at the end of first innings): 40.2%.
Team B’s target= 162*(60.7)/40.2
=244.6.
This is rounded off to the next integer, i.e. 245 runs.
Hence, Team B needs to chase down 245 runs in 22 overs.
I hope this makes the Duckworth-Lewis-Stern method a little bit less vague. However, the table used above is not the exact table used in professional games. Rather, the table is kept confidential, but it can be expected to be of similar structure.
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