The Duckworth Lewis Method, now formally called the Duckworth-Lewis-Stern or DLS method, recalculates a chasing side’s target when rain or another interruption changes a limited-overs match. Rather than simply cutting the target in line with overs lost, it measures the scoring resources available to both teams: overs remaining and wickets in hand. That distinction is why a reduced chase can sometimes have a surprisingly high target, or why a team ahead on the scoreboard may still be behind the DLS par score.
The central idea: cricket has two scoring resources
A batting side has two things with which to score: time, expressed as overs or balls, and wickets. A team with many overs left but only a few wickets in hand has a different scoring potential from a team with the same number of overs but all ten wickets intact. DLS combines those two factors rather than treating an innings as a simple runs-per-over exercise.
At the beginning of a standard 50-over innings, a team has 100% of its resources: 50 overs and ten wickets available. As overs are used and wickets fall, that resource percentage declines. A rain delay can remove a portion of the resources that a side expected to use later. The method then compares the resources available to each team and adjusts the target accordingly.
This is important because batting intent changes with the length of an innings. A side told it has only 25 overs can attack from the outset in a way that a side expecting 50 overs might not. It may take more risks, score faster and accept a greater chance of losing wickets. A straight reduction based only on overs would ignore that tactical difference.
Why a simple run-rate calculation is not enough
Before Duckworth and Lewis developed their model, rain rules such as average run rate and most productive overs were used. Those approaches could produce awkward outcomes because they did not properly account for wickets or the point at which an interruption occurred. A team batting second could be rewarded for accelerating recklessly if rain looked likely, while a bowling side’s best overs could effectively be disregarded under some earlier systems.
The 1992 World Cup semi-final between England and South Africa became the best-known example of the problem. Under the most productive overs rule, a 12-minute delay transformed South Africa’s requirement from 22 runs off 13 balls to 21 off one ball. The incident highlighted why a more balanced mathematical method was needed.
The original Duckworth-Lewis method was first used in international cricket on 1 January 1997, in the second ODI of the Zimbabwe versus England series. The ICC formally adopted it in 1999. After Frank Duckworth and Tony Lewis retired, Australian statistician Steven Stern became custodian of the system, and the method was renamed Duckworth-Lewis-Stern in November 2014.
How DLS calculates a revised target
At its simplest, when the chasing team has fewer resources than the side batting first, the calculation follows this principle:
Par score = first-innings score × (Team 2 resources ÷ Team 1 resources)
The winning target is then the par score rounded up to the next whole run. The score to tie is the par score rounded down. If the chasing team reaches the winning target, it wins; if it finishes exactly on the lower par score, the result is a tie.
For example, if the first team made 254 with its full resources and rain left the chasing side with 90% of its resources, the calculation would be:
254 × 90 ÷ 100 = 228.6
The revised target would be 229 to win, while 228 would be the tie score. This example shows why the displayed target is always one run higher than the rounded-down par score.
The resource percentages are not guessed from the current run rate. They come from tables or approved software that model the relationship between overs, wickets and expected scoring capacity. Cricket Australia’s DLS calculator, for example, allows inputs for the original over limit, runs scored, wickets down, overs lost and interruptions in either innings. It also offers over-by-over and ball-by-ball par-score tables.
What happens when rain interrupts the chase
The most familiar DLS situation occurs when the second innings is shortened. If the chasing side loses overs, it usually loses resources, and its target falls. But the number of wickets already lost matters greatly. A side that is 100 for one when rain arrives retains more potential than a side at 100 for seven at the same stage.
Multiple stoppages are handled separately. At each interruption, the system assesses the resources remaining immediately before play stops and the resources remaining once play restarts. The difference represents the resources lost because of the shortened innings. Those losses are then combined to establish the total resources available to the chasing side.
This is also why the par score matters during a delayed chase. At any point, it indicates the score the chasing side needs to have reached if no further play becomes possible. A side can be below its final target yet ahead of par at the moment rain ends the match. Equally, a team that appears comfortably placed in a conventional run chase may be behind DLS because wickets have fallen quickly.
For readers comparing a chase with pre-match expectations, a Cricket Match Prediction should be separated from the revised in-game equation: once overs are lost, available resources and the DLS par score become more relevant than the original target alone.
Why targets can increase after a first-innings interruption
A common misunderstanding is that a rain-shortened match must always mean a lower target. That is not necessarily true. If the team batting first loses overs during its innings, the side batting second may receive a higher target even when both teams eventually face the same number of overs.
The reason is timing. The first batting side may have planned its innings on the assumption that it would receive more overs. It may have preserved wickets for a late acceleration that rain later removed. The second side, by contrast, begins knowing exactly how many overs it has and can set its approach accordingly. DLS compensates for that informational advantage.
An illustration from the earlier D/L explanation makes the point. If Team 1 loses its final overs after batting cautiously in expectation of a longer innings, merely asking Team 2 to surpass its recorded score would not reflect the first side’s lost opportunity. The revised target may therefore rise to account for the additional resource value available to the chasing team, which can plan its aggression from ball one.
Standard tables and professional calculations
The original method could be applied using published resource tables and a calculator. These tables convert combinations of overs remaining and wickets lost into resource percentages. For instance, an older Duckworth-Lewis table showed that with 30 overs remaining and two wickets down, a batting team had 68.2% of its 50-over resources left. If an interruption then reduced the remaining allocation to 20 overs with the same wickets lost, the resource percentage fell to 54.0%, meaning 14.2% of resources had been removed.
Modern elite cricket uses the Professional Edition, which is more sophisticated than a basic public table. It adjusts for scoring conditions and incorporates a scoring parameter linked to the first innings. The precise resource values used in that edition are not publicly available, so authorised computer software is used for official calculations. This is why an informal online calculation may be useful for understanding the method but should not be assumed to reproduce an official target exactly.
Reading a DLS result correctly
A scorecard description such as “won by 19 runs (D/L method)” means the margin has been determined against the revised target, not necessarily against the original first-innings total. The most useful numbers to examine are the revised target, the par score at the point play ended, the overs actually available and wickets lost by the chasing side.
DLS does not attempt to predict what would definitely have happened without rain. It provides a consistent way to compare two innings when each team did not have identical opportunities. Its purpose is not to make a shortened contest perfectly equivalent to an uninterrupted one, but to produce a target based on the relative scoring resources each side had.
Conclusion
The Duckworth Lewis Method works because it recognises that overs and wickets cannot be separated when judging a cricket innings. By comparing the resources available to both teams, DLS produces a revised target that reflects timing, batting freedom and wickets in hand—not just the number of overs removed by rain.
