Why a simple run-rate doesn't work
Imagine Team A scores 300 in 50 overs. Rain reduces Team B's innings to 25 overs. Halving the target to 150 sounds fair — but it isn't. Team B now has all 10 wickets to score 150 in 25 overs, which is far easier than scoring 300 in 50.
The Duckworth-Lewis-Stern method exists to fix exactly this kind of imbalance. It treats overs and wickets as combined 'resources' a team has available.
The resources concept
Every team starts an innings with 100% resources — 50 overs and 10 wickets. As overs are bowled and wickets fall, the resource percentage drops, according to a lookup table maintained by the ICC.
Lose a few wickets early and your resources drop faster than the over count alone would suggest. Bat through with wickets in hand and you preserve resources for the death overs.
How a revised target is calculated
If Team B's innings is shortened, DLS works out the percentage of resources they LOST compared to what Team A had. The revised target is:
Team A's score × (Team B's resources ÷ Team A's resources) + 1
If Team B has MORE resources (rare — usually means Team A was also rain-affected), the target goes up. If Team B has fewer, the target comes down — but not as much as a naïve run-rate split.
Worked example
Team A: 250/6 in 50 overs (used 100% resources).
Team B starts chasing, plays 20 overs and is 100/2 when rain stops play. The match is reduced and Team B will only get another 10 overs (30 in total).
Team B had 100% resources when they started but only got to use roughly 71% (because of the lost overs). Their revised target becomes 250 × 0.71 + 1 ≈ 178.
If they were on 100/2 with 30 overs played and the rain washed the match out at that point, the par score for that exact ball would tell us who won.
What the 'par score' on TV means
During a chase, broadcasters show a live DLS par score. That number is what the batting side WOULD need to be on right now to be level if rain ended the match this ball. Ahead of par = winning. Behind par = losing.
When play is finally abandoned, whoever is on the right side of par at the last completed over wins.
Why 'Stern' was added
Frank Duckworth and Tony Lewis published the original method in 1997. Steven Stern, an Australian statistician, refined the formula in 2014 to better reflect modern T20-era scoring rates — hence DLS instead of just D/L.
Frequently asked
Is DLS used in Test cricket?+
No. Tests have no over limits and can be drawn, so DLS doesn't apply.
Is DLS used in T20s?+
Yes. A minimum of 5 overs per side must be completed in T20Is for DLS to produce a result.
Is DLS fair?+
It's the most accurate method we have, but it can favour the batting side when wickets in hand are high — captains know this and adjust tactics in rain-threatened games.
Who chooses to use DLS?+
It's mandated by the ICC for all official limited-overs matches affected by lost time.