Few things frustrate cricket fans more than rain during a limited-overs match. When overs are lost, the target for the chasing team is recalculated using the Duckworth-Lewis-Stern (DLS) method. It looks mysterious on TV, but the idea behind it is logical.
A short history
The method was created by statisticians Frank Duckworth and Tony Lewis and was first used in international cricket in 1997. After Professor Steven Stern updated the model to reflect modern scoring patterns, it was renamed Duckworth-Lewis-Stern in 2014.
The key idea: resources
A batting team has two resources: overs remaining and wickets in hand. With 50 overs and 10 wickets, a team has 100% of its resources. As overs are bowled and wickets fall, that percentage drops.
Wickets matter as much as overs. A team that has 10 overs left with 9 wickets in hand can attack freely, while a team with 10 overs left and 2 wickets in hand must be careful. DLS reflects this difference.
How the target is set
- The resources available to both teams are calculated using DLS tables or software.
- If the chasing team has fewer resources than the team that batted first, its target is reduced in proportion.
- If the chasing team has more resources (for example, when the first innings was interrupted), its target can be increased.
That is why a target sometimes looks oddly specific, such as 187 runs from 33 overs.
The par score
During a chase you will often see a DLS par score on screen. It shows how many runs the chasing team needs at that moment to be ahead if no more play is possible. Captains watch it closely when rain is forecast.
Minimum overs for a result
A result is only possible if both teams have faced a minimum number of overs: 20 overs each in ODIs and 5 overs each in T20 matches. If that minimum is not reached, the match is declared a no result, unless a reserve day is available.
Is DLS fair?
No system can perfectly predict what would have happened without rain, and DLS has its critics, especially in very short T20 games. Still, it is widely accepted as the fairest method available and is used in all international limited-overs cricket.
Next time rain stops play, look at the overs left and the wickets in hand together. That combination is exactly what DLS measures.
