DLS Method in Cricket Explained
How the Duckworth-Lewis-Stern method works, why cricket needs it, and how revised targets are calculated when rain interrupts a limited-overs match.
The Duckworth-Lewis-Stern (DLS) method is the mathematical formula used to calculate revised targets in limited-overs cricket when play is interrupted by rain or other delays. It replaced the previous target-revision methods that were widely criticised as unfair, and was adopted by the ICC in 1999.
Why DLS is Needed
When overs are lost to rain, simply reducing the target proportionally is unfair because it ignores the value of wickets remaining. A team chasing 300 in 50 overs with 6 wickets in hand and 20 overs remaining is in a very different position from the same team with 2 wickets remaining. DLS accounts for both overs remaining and wickets in hand when calculating the revised target.
The Resource Model
DLS treats each combination of overs remaining and wickets in hand as a 'resource percentage'. When overs are lost, the total resource available to both teams changes. The team with fewer resources receives a proportionally adjusted target. If the team batting first had interruptions, their score is recalibrated upward; if the chasing team loses overs, the target is reduced.
Target vs Par Score
In DLS, there are two important numbers: the revised target (the total the chasing team needs to exceed) and the par score (the score the chasing team should have reached at any given point during the interrupted innings). If rain stops play and a match cannot resume, the team whose score was above the par score at that moment wins — or if it is equal, the match is tied.
Famous DLS Controversies
The most famous DLS controversy is the 1992 Cricket World Cup semi-final between England and South Africa. Under the old rain rule (not DLS), South Africa's revised target went from 22 runs off 13 balls to 21 runs off 1 ball — a mathematically impossible task. DLS was specifically designed to prevent outcomes this absurd. Even with DLS, marginal cases still generate debate.
Frequently asked questions
Who invented the DLS method?
The method was invented by English statisticians Frank Duckworth and Tony Lewis in the 1990s. It was originally called the Duckworth-Lewis method (D/L). Professor Steven Stern later updated the formula to reflect changes in scoring rates across modern cricket, and the ICC officially renamed it to DLS in 2014 to credit his contribution.
What is the minimum number of overs needed for a DLS result?
The match minimum is 20 overs per side in ODIs and 5 overs per side in T20Is for a valid result. If the minimum is not met, the match is abandoned with no result. In knockout stages (World Cups), reserve days are often used to allow the minimum to be completed rather than abandoning a match.
Can a team win by DLS even if they were behind when rain came?
Yes — if the par score calculation places the chasing team ahead at the moment of interruption, they can win even though their raw score was lower than the target. This is intentional: DLS rewards teams that have used their resources well (wickets and overs) rather than simply comparing raw totals.