GUWAHATI: Frank Duckworth, the renowned English statistician and co-creator of the Duckworth-Lewis-Stern (DLS) method, has passed away at the age of 84. His death was reported on Friday, June 21, according to media reports.
Duckworth, alongside fellow statistician Tony Lewis, developed the groundbreaking Duckworth-Lewis method, a revolutionary formula used to determine fair outcomes in cricket matches affected by rain. This method, first introduced in international cricket in 1997, has become a cornerstone in the sport.
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In 2001, the International Cricket Council (ICC) officially adopted the Duckworth-Lewis method as the standard approach for recalculating revised targets in rain-affected matches. After Duckworth and Lewis retired, the method underwent further refinements by Australian statistician Steven Stern.
The updated version, now known as the Duckworth-Lewis-Stern (DLS) method, continues to be integral to cricket, factoring in various elements such as the number of wickets remaining and overs lost to accurately determine the revised targets for teams batting second. In acknowledgment of their significant contributions to cricket, both Duckworth and Lewis were awarded MBEs (Member of the Order of the British Empire) in June 2010.
ICC mandates that all matches will utilise the Stern Edition of the Duckworth-Lewis Method (DLS Method) to determine revised targets in rain-interrupted games. This methodology ensures that the complexity of resource allocation is accurately accounted for when play is disrupted due to weather conditions.
The Stern Edition of the DLS Method, which is an evolution of the original Duckworth-Lewis system, is applied to all matches where interruptions alter the number of overs available for either team. This advanced system is designed to calculate revised targets more precisely, reflecting the real-time situation of the match.
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The latest version of the ‘ICC Duckworth-Lewis-Stern Calculator’ is used to determine the revised targets. This calculator, distributed by the ICC, incorporates the updated algorithm that factors in the resources available at any given point in the match.
Backup systems will be in place to ensure continuity in case of any technical issues with the primary calculator. Should both the main and backup systems fail, the ICC will revert to the Duckworth-Lewis Standard Edition (the version used before October 2003) for calculations.
The DLS Method adjusts targets based on the remaining resources, defined by the number of overs left and the number of wickets lost. Unlike the average run rate method, the DLS Method considers these variables to provide a more equitable target for the team batting second (Team 2).
When a match is interrupted, it is crucial to determine the resource percentage lost. This involves checking the resource percentages at the start and resumption of the suspension period and calculating the difference. If the suspension ends the innings, the remaining resource percentage is considered lost.
To set the revised target for Team 2:
• The original number of overs per innings and the resource percentage available to Team 1 is noted.
• Any suspensions in Team 1’s innings is adjusted and the total resource lost is calculated.
• Team 2’s resource percentage at the start of their innings is determined, based on their allocated overs.
• If the resource percentage available to Team 2 (R2) is less than the resource percentage available to Team 1 (R1), the target is adjusted downwards using the ratio of R2 to R1.
• If R2 is greater than R1, an upward adjustment is made by adding extra runs based on the additional resources.
Penalty runs awarded during the innings will affect the scores but will not alter the DLS calculations directly.
To illustrate, consider a match where Team 1 scores 250 runs in 50 overs. If interruptions reduce Team 2’s resources to 86.8%, their revised target becomes 218. In cases of multiple suspensions, the target is recalculated to reflect the accumulated resource changes.
In a real-world example from an ODI between India and Pakistan in 1996, rain interruptions led to the adjustment of Team 2’s target after both a mid-over termination and a delayed start to their innings.
