Duckworth-Lewis-Stern Method: How Rain Affects Cricket Targets Explained
The Duckworth-Lewis-Stern (DLS) method is the mathematical system used to recalculate batting targets in limited-overs cricket when rain or other interruptions reduce the number of overs available. It replaced the flawed 'highest scoring overs' rule responsible for cricket's most notorious rain-rule injustice — the 1992 World Cup semi-final South Africa 22-off-1-ball disaster. DLS uses the concept of 'resources' (overs remaining × wickets in hand) to set fair revised targets.
Why rain rules are needed: in limited-overs cricket (ODI and T20), each team has a fixed number of overs to bat. When rain stops play, the match may be shortened — one or both teams may have fewer overs available than originally allocated. Without a rain rule, the match would simply be abandoned (no result). With a rain rule, matches can often produce a result even after interruption. The problem: if Team A bats 50 overs and scores 280, then rain reduces Team B's innings to 30 overs, Team B's target of 281 from 30 overs is clearly unfair (50-over targets are too high for 30-over chases). A revised target must be calculated. The old methods and their failures: (1) The 'run rate' method: revising the target proportionally by run-rate. Problem: team batting second gets credit for overs remaining but not for wickets lost (a team 0/100 off 20 overs has far more potential than a team 9/100 off 20 overs, but a simple run rate doesn't capture that). (2) The 'highest scoring overs' method (used 1990-1997): reduces the target by removing the highest-scoring overs from the batting team's innings. This caused the South Africa vs England 1992 semi-final disaster (South Africa revised target of 22 from 1 ball).
Resources Concept Explained
The DLS resources concept: the Duckworth-Lewis method (introduced 1997, renamed Duckworth-Lewis-Stern after Professor Steven Stern updated the system in 2014) is based on the insight that a batting team's ability to score runs depends on two resources: (1) Overs remaining; (2) Wickets in hand. Each combination of overs remaining + wickets in hand corresponds to a percentage of the team's total expected run-scoring capacity. When a team starts their innings: they have 100% resources available (50 overs, 10 wickets = 100%). As they bat through the innings, resources reduce — either by using up overs or by losing wickets. The DLS tables: the ICC maintains tables of 'resource percentages' for each combination of overs remaining and wickets lost. For example: 50 overs remaining, 10 wickets = 100% resources. 25 overs remaining, 10 wickets = approximately 67% resources. 25 overs remaining, 5 wickets = approximately 44% resources (wickets lost significantly reduce the resource value). Rain rule calculation: when rain interrupts, the DLS method calculates how many resources each team had/will have available, and scales the target proportionally.
T20 Rain Rules
DLS in T20 cricket: the DLS method applies to T20 cricket (20-over format) as well as ODI cricket (50-over format). The same resource percentage tables are used, but adjusted for 20-over context. T20-specific issues: T20 matches are much shorter, so rain interruptions have a proportionally larger impact on the match. A 5-over reduction from a 20-over match (25% of overs lost) has far more impact than a 5-over reduction from a 50-over match (10% of overs lost). Minimum overs for a result: for a T20I match to produce a DLS result, each team must have faced a minimum of 5 overs. For an ODI, the minimum is 20 overs per side. If even the first team's innings hasn't been completed to the minimum, the match is typically abandoned with no result. The Super 12 and knockouts at World Cups: DLS has decided several World Cup knockout matches, including the 2022 T20 World Cup semi-final between India and England, which was abandoned and the reserve day produced no play either — causing the match to be counted as India advancing (as they had the higher group stage record).
1992 Old Rule vs DLS
The 1992 World Cup disaster that triggered DLS: the 1992 ICC World Cup used the 'average run rate per over from highest scoring overs' method. In the semi-final at Sydney (March 22, 1992): England scored 252/6 in 45 overs. South Africa needed 252 in 45 overs (reduced match). South Africa were 231/6 off 42.5 overs (needing 22 from 13 balls) when rain interrupted for 12 minutes. The revised target under the 1992 method: removed the lowest-scoring over from England's innings (a 0-run over) and reduced South Africa's target by those runs. The result: South Africa's revised target was set to 22 runs from 1 ball — an impossible target. South Africa lost. The injustice: South Africa were on track to win the match when rain stopped play. Under a fair rain system, they would have faced approximately 6-7 runs required off 1 ball (achievable with a lucky boundary). The 1992 rule robbed South Africa of a potential World Cup Final berth. This injustice directly motivated Duckworth and Lewis to develop their resources-based mathematical model, which was adopted by the ICC in 1997 and has been used in all major limited-overs cricket since.
Frequently asked questions
How does the Duckworth-Lewis-Stern (DLS) method work?
The Duckworth-Lewis-Stern (DLS) method calculates revised batting targets in limited-overs cricket (ODI and T20) when rain or interruptions reduce the number of overs available. It works by measuring each batting team's 'resources' — a combination of overs remaining and wickets in hand — and setting the revised target in proportion to the resources available to each team. The core principle: a team with 30 overs remaining and 10 wickets = more resource than a team with 30 overs remaining and 5 wickets (wickets add batting capacity). The DLS tables (maintained by the ICC) assign a resource percentage to every combination of overs remaining and wickets lost. When rain interrupts: if resources are lost (overs cancelled), the target is adjusted so that the batting team's required runs are proportional to the resources they have available. If Team 2's innings is interrupted: the revised target = (Team 1's score × Team 2's available resources) / Team 1's available resources. The DLS calculation is run by official ICC-licensed scoring software at all international matches — no manual calculation is used. Frank Duckworth and Tony Lewis developed the original system in 1997; Professor Steven Stern updated it in 2014 (adding the 'S' to DLS — Duckworth-Lewis-Stern).
Why was the 1992 cricket rain rule unfair?
The 1992 ICC World Cup rain rule was unfair because it did not account for wickets — it only removed overs based on the lowest-scoring overs from the first team's innings, creating mathematically absurd revised targets. The rule: when overs were lost from the second team's innings, the target was reduced by the runs scored in the lowest-scoring over(s) of the first team's innings. This sounds logical but fails because: (1) it does not consider the second team's batting position (how many wickets they have lost); (2) it does not recognise that overs toward the end of an innings are typically more valuable than early overs; (3) it can produce targets that require multiple runs off a single remaining ball. The 1992 semi-final example: South Africa needed 22 from 13 balls against England (a competitive but achievable target). After a 12-minute rain interruption, the revised target was 22 from 1 ball — which required hitting a six AND a six AND another four from one delivery, a physical impossibility. The lowest-scoring over in England's innings happened to be a 0-run over late in their innings (a maiden-equivalent in ODI cricket). When that over was subtracted from the target, it reduced South Africa's runs-needed by 0 but also reduced their available balls — leaving them needing the full original runs in 1 ball.
What is the minimum overs rule in cricket?
In limited-overs cricket, there are minimum over requirements for a match result to be possible: In ODI cricket: each team must have the opportunity to bat at least 20 overs for a match to produce a result. If rain prevents either team from facing 20 overs, the match is abandoned as no result (or, in tournaments with reserve days, moved to the reserve day). If the first team has batted their full allocation but rain prevents the second team from facing 20 overs, the match is also abandoned. In T20I cricket: each team must have the opportunity to bat at least 5 overs for a result to be possible. The 5-over minimum (reduced from previous requirements) was set to allow more T20 matches to produce results despite rain. In tournament knockout matches (World Cup quarter-finals, semi-finals, finals): reserve days are allocated for abandonment scenarios — the same minimum over rules apply on the reserve day. If play is impossible on both the match day and the reserve day: the team with the better group-stage record typically advances (in ICC tournament rules). In bilateral ODI series (not a World Cup): abandoned matches are generally replayed if possible or recorded as no results with a split of points (or no points awarded).