The DLS Method Explained: How Rain-Affected Targets Are Set
Understand the Duckworth-Lewis-Stern method: how resources, overs and wickets are used to set fair targets when rain shortens a limited-overs match.
Rain is one of cricket’s oldest problems. When a limited-overs match is interrupted, the second team can no longer be given the same target in fewer overs without some adjustment. The Duckworth-Lewis-Stern method, universally abbreviated as DLS, is the system the ICC uses to set a fair revised target in these situations.
Where the method comes from
The original system was devised by two English statisticians, Frank Duckworth and Tony Lewis, and was first used in international cricket in 1997 and formally adopted by the ICC in 1999. After Lewis retired, the Australian academic Steven Stern took over maintenance of the system, and from late 2014 it became known as Duckworth-Lewis-Stern. The aim has always been to give both sides an equivalent chance when overs are lost.
The key idea: resources
A simple run-rate calculation is unfair because a team’s ability to score depends on two things, the number of overs left and the number of wickets in hand. DLS treats these together as a resource. A team starting a 50-over innings has 100 per cent of its batting resources. As overs are used and wickets fall, that percentage drops.
Having lots of wickets in hand allows a side to attack, so losing early wickets reduces resources faster than losing overs. The method reflects this by assigning a resource percentage for every combination of overs remaining and wickets lost.
How a revised target is worked out
In principle, the method compares the resources available to each team. If both teams have the same resources, the target stays as it was. If the chasing team has fewer resources than the first side had, the target is reduced in proportion; if it has more, the target is increased. The resulting figure is described as a par score, and the chasing side must beat it to win.
Match officials do not calculate this by hand. They use official software, which applies the standard tables and, in higher-scoring conditions, adapts to the scoring patterns of the match. The ICC uses a dedicated version for professional games.
Common situations
- Rain before the first innings: both teams may simply have a reduced number of overs, and no adjustment is needed beyond the shorter match.
- Rain during the first innings: the first team’s total may be treated as a resource-weighted score, and the chasing team’s target is adjusted.
- Rain during the chase: the target is recalculated for the number of overs now available, taking into account wickets already lost.
- Rain stops the chase altogether: the winner is decided by comparing the score with the par score at that point.
Minimum overs for a result
A match needs a minimum amount of play to produce a result. Under the standard ICC playing conditions, each team must usually face at least five overs in a T20 match and 20 overs in an ODI, although tournament rules may vary. If this is not achieved, the match is declared a no-result.
Why people criticise it
DLS is generally regarded as the fairest available method, but it is not immune to complaint. Critics point out that targets can feel counter-intuitive, and that the system is built around averages that may not match the particular conditions of a match. Supporters note that it has been refined repeatedly and is far more consistent than earlier methods, which sometimes produced widely criticised results.
How to read DLS targets in a match report
When you see a revised target, remember that it is designed to balance the resources of both sides rather than the raw runs. A target of, for example, 140 from 15 overs does not mean the chasing side needs to score at the same pace as the first team did; it means that with fewer overs but all wickets in hand, 140 is considered equivalent to the original total.
During a chase, broadcasters often show a par score. Being ahead of it means the chasing team would win if play ended at that moment. Our guide to net run rate explains how interrupted matches can also affect tournament tables.
Frequently asked questions
What does DLS stand for?
DLS stands for Duckworth-Lewis-Stern, named after statisticians Frank Duckworth, Tony Lewis and Steven Stern.
Why does DLS consider wickets as well as overs?
Wickets in hand allow a team to bat more aggressively, so both overs and wickets together determine a team’s scoring potential, or resources.
What is the par score?
The par score is the total the chasing team must have reached at a given moment to be level with the revised target had the match stopped there.