Duckworth-Lewis-Stern (DLS) Method Explained — How Rain Decides Cricket Matches

The Duckworth-Lewis-Stern method — usually shortened to DLS — is how cricket decides a limited-overs match shortened by rain or bad light. It replaces the original target with a revised one that's fair to both sides. Frank Duckworth and Tony Lewis devised it in 1997; Steven Stern refined it in 2014, adding his name to the title.

Why DLS exists

Cricket's earlier rain rules were notoriously unfair. The most-bashed example: South Africa needing 22 off 1 ball in the 1992 World Cup semi-final after rain cut their chase. The earlier formulas treated overs and wickets as separate, ignoring how they interact — five overs with all ten wickets is a very different beast from five overs with one wicket left.

DLS captures that interaction through a single concept: resources.

Resources — the core idea

Each team starts an innings with 100% resources, defined as a function of overs remaining AND wickets in hand. As you use overs or lose wickets, your resources drop. Lose three wickets in the first five overs of a T20 and you've used proportionally more resources than the over count alone would suggest.

DLS publishes a resource table covering every combination of overs remaining and wickets lost. When the rain interrupts, both sides' resource percentages are looked up. The revised target is then proportional to the difference.

Three common scenarios

1. Rain interrupts Team 1's innings, no further play

Match is declared no-result if Team 2 hasn't faced enough overs (5 in T20, 20 in ODI). Otherwise DLS sets a par score Team 2 needed to be ahead of when play stopped.

2. Team 1 finishes, then rain delays Team 2

Team 2's chase is shortened. DLS calculates how much of Team 2's resources were lost to the delay and sets a revised target proportional to the reduction.

3. Rain mid-chase

When play stops mid-innings, DLS provides a par score: if Team 2 was at or above par at the cutoff, they win; otherwise Team 1 wins. The umpires announce the par score after each interruption so the chasing side knows where it stands.

What changed in 2014 — the Stern update

Steven Stern recalibrated the resource tables using a larger dataset of T20 cricket. The old Duckworth-Lewis tables were built mostly on ODI data and tended to give chasing teams an edge in T20 contexts. The DLS revision tightened the maths and is now used across every format.

Standard vs Professional Edition

Two flavours exist. The Standard Edition uses a single table that anyone with a calculator can apply. The Professional Edition feeds extra match context — particularly very high first-innings scores — into a more nuanced model and is used in international cricket. The Professional Edition is the version you see on TV graphics.

Common misunderstandings

• DLS doesn't 'punish' a team — it sets a target reflecting the resources actually available.
• Losing wickets in a DLS scenario can shift the par score even if no further overs are bowled.
• DLS is not used in Tests — Test matches have no over limit, so rain just costs time, not resources.