The Duckworth-Lewis-Stern (DLS) method is a mathematical formulation designed to calculate the target score for the team batting second in a limited-overs cricket match interrupted by weather or other circumstances. The method was devised by English statisticians Frank Duckworth and Tony Lewis, and later updated by Australian academic Steve Stern, which is why it is also known as the Duckworth-Lewis-Stern method.
The DLS method aims to set a statistically fair target for the second teams innings, which is the same difficulty as the original target. It takes into account the two resources available to both teams: overs to play and wickets remaining. The target is adjusted proportionally to the change in the combination of these two resources.
Here's a step-by-step explanation of how the DLS method works:
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Resource calculation: Each team starts with 300 balls (overs) and ten wickets. As the innings progresses, these resources deplete, reaching zero when a team either plays out all 300 deliveries or loses all ten wickets.
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Adjustment for early wickets: Sometimes, when the team batting first loses several early wickets, a reduction of overs is beneficial to them. In such cases, the DLS method will readjust the target for the chasing team based on the revised number of overs and wickets remaining.
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Example: In the second game of the 2017 Champions Trophy, Australia's 46-over target stayed at 292 (New Zealand made 291) after a four-over loss when New Zealand were 67 for 1 in 9.3. Had they been 67 for 4 and then finished with the same total, Australia's target would have come down to 284.
The DLS method has been officially adopted by the International Cricket Council (ICC) for calculating target scores in rain-affected matches since 1999. It is considered a fair and effective way to determine target scores in limited-overs cricket matches interrupted by weather or other circumstances.
