The Duckworth-Lewis-Stern (DLS) method is the calculation cricket uses to set a revised target when rain, bad light or another interruption shortens a limited-overs match. It is named after the statisticians Frank Duckworth, Tony Lewis and Steven Stern.

It works on one idea: each side starts an innings with 100 per cent of two resources, overs and wickets. A target should be adjusted in proportion to how much of those resources each side actually got. A team that loses overs to rain has less scoring potential, but how much less depends on how many wickets it still has in hand.

How the DLS method works

DLS assigns a resource percentage to every combination of overs remaining and wickets lost. If the side batting second has fewer resources available than the side batting first had, the target comes down in proportion. If it somehow has more, which happens when the first innings is the one cut short, the target goes up.

Take a side that makes 250 from its full 50 overs, so it used 100 per cent of its resources. If rain then cuts the reply to 40 overs before a ball of it is bowled, the chasing side starts with about 89.3 per cent of its resources under the published Standard Edition table. The target becomes 250 multiplied by 0.893, which is 223.25, so the par score is 223 and the target to win is 224.

When can a DLS result be given?

DLS cannot produce a result out of nothing. The side batting second must face a minimum amount of cricket first: 20 overs in a one-day international and five overs in a T20. Below that, the match is a no result, however one-sided it looked.

International cricket uses the Professional Edition, which runs as software and whose underlying figures are not published, so an official DLS target cannot be reproduced by hand. The Standard Edition table is published for club cricket and public calculators.

History of the DLS method

Duckworth and Lewis published their method in the mid-1990s. It was first used in international cricket in a Zimbabwe against England match in 1997, and the International Cricket Council adopted it in 1999. After Steven Stern took over as custodian and recalibrated it for faster modern scoring, it was renamed the Duckworth-Lewis-Stern method in November 2014.

The method came into focus again this week in New Zealand, where both of India's first two ODI wins over the hosts, by five wickets in Auckland and by four runs in Wellington, were decided by DLS before rain washed out the third match in Hamilton entirely.

Source: SportsAdda and Wikipedia.