Duckworth-Lewis-Stern (DLS) Method Explained Simply
Understand the Duckworth-Lewis-Stern method step by step — how rain-affected cricket matches are decided, why DLS exists, and common criticisms.
Rain-affected cricket matches used to be settled by crude formulas — highest run rate in a fixed number of overs — that led to absurd results. The Duckworth-Lewis-Stern (DLS) method replaced these with a mathematically rigorous system that accounts for a team's remaining resources: overs AND wickets.
The Core Insight: Resources = Overs + Wickets
The key innovation of DLS is recognising that a batting team has two resources: the overs remaining AND the wickets in hand. A team with 10 wickets and 20 overs has far more resources than a team with 5 wickets and 20 overs. Traditional rain rules ignored wickets entirely.
How DLS Works: A Step-by-Step Example
Team A bats first and scores 250 in 50 overs. Rain interrupts before Team B can bat. Officials decide Team B will chase 250 in just 30 overs. Is 250 still fair? DLS says no.
- Calculate Team A's resource used: 50 overs, all 10 wickets available = 100% resources.
- Calculate Team B's resources: 30 overs remaining, 10 wickets = approximately 75.1% of resources.
- Team B's par score = 250 × (75.1 ÷ 100) = ~188 runs.
- Team B must score 189 in 30 overs to win.
When Team 2 is Interrupted Mid-Innings
The calculation becomes more complex when Team 2 is already batting and rain interrupts. The DLS method recalculates the par score in real time based on how many wickets Team 2 has lost and how many overs remain at the moment of interruption.
Example
Team B needs 250 from 50 overs. After 20 overs they have scored 80 for 3 wickets (resources used: ~37%). Rain falls. Play resumes with 15 overs left (resources remaining from that point with 7 wickets in hand: ~32%). DLS recalculates Team B's target for the remaining overs based on the combined resource situation.
Why 'DLS Par Score' Matters in Real Time
During live play in rain-threatened matches, the television broadcast and scoreboard show the DLS par score — the score Team 2 would need to have reached at that exact moment to be ahead on DLS. If the match is abandoned immediately, whichever team is ahead of par is declared the winner.
The 'Stern' Update: Why the Method Was Renamed
Frank Duckworth and Tony Lewis developed the original method in the 1990s and it was adopted by the ICC in 1997. Professor Steven Stern took over maintenance of the method in 2014, refining the resource tables to better reflect modern run-scoring rates — particularly in T20 cricket where scoring in the final overs is dramatically higher than in earlier eras.
Common Criticisms of DLS
- It can produce targets that seem unfair when a team was positioned well before rain stopped play
- The public-facing simplification obscures complex statistical modelling, making it feel opaque
- T20 matches often need very few overs — 5-over DLS targets can feel arbitrary
- Teams batting second in crucial moments can be disadvantaged by pitch conditions worsening after rain
- The 'G50' scaling factor used in high-scoring matches is not publicly released, reducing transparency
DLS in T20 Cricket
DLS is used in T20 international and major T20 competitions. However, T20 DLS has a minimum of 5 overs required for a valid result. This means that if rain prevents more than 5 overs from being bowled in total, the match is usually abandoned without a result (or decided on the Super Over in knockout games, if permitted by the competition regulations).
Frequently asked questions
What is the difference between DLS par and DLS target?
The DLS target is the total runs Team 2 must surpass to win over the full revised innings. The DLS par score is the live score Team 2 needs to have reached at any given moment during their innings. If the game is abandoned mid-innings, the team ahead of the par score at that moment wins.
Why does Team 2 sometimes get a lower target with DLS even in conditions that seem fair?
DLS accounts for resources, not pitch or weather fairness. If Team 1 batted in good conditions but Team 2 faces far fewer overs, DLS reduces the target proportionally to the resources available — it does not adjust for wicket quality, pitch deterioration, or dew.
Has DLS ever been criticised for a major match result?
Yes. Notably, the 1992 Cricket World Cup semi-final between England and South Africa used an older rain rule (not DLS) that produced a famously absurd target. Had DLS been available, the result would have been different. DLS itself has faced criticism in several T20 World Cup knockout games where short rain-revised targets seemed counter-intuitive.
Is the DLS method used in all cricket formats?
DLS is the ICC's official rain-rule for ODIs and T20Is. Test matches are not governed by DLS — they can draw if time is lost and a result is impossible, and they have specific rules for minimum overs required for a result in certain match situations.