Duckworth–Lewis–Stern Method
Rain can play spoilsport in a cricket match. Unlike football and other outdoor sports, a full quota of overs in a cricket match is never possible if the “Rain Gods” decide to intervene. In such a scenario, the match either gets canceled or a shortened match takes place. Duckworth-Lewis Stern method is a technique through which targets are calculated in rain-shortened limited-overs matches.
What is the Duckworth-Lewis Stern method? From where this name was derived? What are some of the famous instances where the DLS method was employed to decide the result of cricket matches? These are a few questions that we look forward to answering through this piece.
What is Duckworth-Lewis Stern Method?
DLS or Duckworth-Lewis Stern method is a mathematical formula that is designed to calculate the winning score for a team batting second in a rain-curtailed match. DLS is also used to calculate the target score if any unfavorable weather conditions become a hurdle for the completion of a cricket match. Through this method, a fair target is set for the team batting second.
Who Invented the Duckworth-Lewis Stern Method?
Frank Duckworth and Tony Lewis are two statisticians who invented the Duckworth-Lewis Stern method. Later, Professor Steven Stern from the Department of Statistics of the Queensland University of Technology became the custodian of the D/L method. The Duckworth-Lewis method was renamed to the Duckworth-Lewis Stern method on November 2014.
How Duckworth-Lewis Stern Method Came into Existence?
Earlier, methods like the Average Run Rate (ARR) or Most Productive Over (MPO) were tried to calculate a near-perfect target for the team batting second in a rain-curtailed cricket match. Both these methods failed to account for one important factor – WICKETS! It is an important factor because the team batting second had all their wickets intact. It tilted the balance of the match towards the team batting second.
Supposedly the team batting first lost 3 wickets within the first 10 overs. They naturally wanted to consolidate leading to a lower run-scoring rate. The same could have happened with the second team if the pitch assisted bowlers in the initial phase of the second innings. But, just because rain intervened, only one team should not reap its benefits.
How is a Target Calculated Using Duckworth-Lewis Stern Method?
With the Duckworth-Lewis Stern method, a target for the team batting second in a rain-truncated match is decided by taking into consideration how the first team would have batted if they had all their wickets intact. It considers the fact that a team batting before a rain interruption would have batted differently had they known there will be an interruption. The Duckworth-Lewis Stern formula is given below –
Par score of the 2nd team = Final score of the 1st team (Resources available for the 2nd team/Resources available for the 1st team).
How DLS is Different from DL?
The previously existent Duckworth-Lewis method favored the teams batting second hugely in a rain-truncated. The new DLS method is somewhat successful in calculating a perfect target for the second team by considering various factors. This is the difference in layman’s terms. Let us try to understand it with the help of an example.
Eg – In the D/L method, a team batting before the rain interruption scores 200 runs in 20 overs at a run rate of 10 rpo. If the team batting second can bat for 10 overs, their target becomes 100 (because the first team scored at 10 rpo). No other factors are considered that make the chasing team’s task much easier. In DLS, the fact that how the first team would have batted had they known there was an interruption around the corner is considered before setting a target for the second team.
What is the Difference between Par Score and Target?
When a team is “X” wickets down and chasing, the par score is the total they should have reached at the time of the interruption. The target score is the amended number they need to reach after the interruption. At that stage of the game, the scores are level if a chasing team score exactly par. Before an interruption, par scores are calculated, whereas targets are computed after an interruption. While the par score varies depending on how many wickets are lost, the target is a fixed number.
Famous DL/DLS Outcomes
Here are some outcomes of cricket matches that were decided using the Duckworth-Lewis and Duckworth-Lewis Stern methods –
- 1992 World Cup, England vs South Africa, Sydney – South Africa needed 22 runs from the final 13 deliveries of the match when the rain interrupted. After the match resumed, South Africa was asked to get 22 runs from 1 delivery. According to the earlier D/L method (and the MPO method), the final two overs of the English innings were maiden. This meant out of the 13 deliveries, 12 of them were automatically declared “dead” for South Africa
- 2003 World Cup, South Africa vs Sri Lanka, Durban – The par score for South Africa in this match was set to 229 in 45 overs. Mark Boucher, the then Wk-Batter for South Africa did not take a single in the last ball of the 45th over. Rain interrupted and the play could not be resumed after. South Africa was sitting on the par score so the match was tied
- 2022 T20 World Cup, South Africa vs Zimbabwe, Hobart – South Africa was set a target of 64 from 7 overs due to multiple rain interruptions. South Africa was 51 for no loss after 3 overs. Rain resumed at Hobart that left split the points between both the teams
- 2022 T20 World Cup, England vs Ireland, MCG – the eventual champions were defeated by a less-fancied and young Irish team by 5 runs. England was well on course to win the game even though wickets were falling at regular intervals. Suddenly the clouds gathered and halted the play while England was still 5 short according to the DLS sheet. Sadly, the game could not resume and Ireland was declared the winners
There are several other instances like the 3rd T20I between India and New Zealand played at Napier on 22nd November 2022. The match was tied as India found themselves on 74, the par score after 9 overs in the rain-curtailed match.
