Barring Virat Kohli’s half-centuries and Shaheen Afridi’s wickets, rain has been a regular feature at the ICC Men’s T20 World Cup 2022. To calculate par scores and revised targets in rain-affected matches, the Duckworth-Lewis–Stern (DLS) method is used.
While the calculations are carried out by a software, the basis could be comprehended by cricket enthusiasts. Let us understand how DLS works:
Predecessors of the DLS method, Average Run Rate (ARR) and Most Productive Overs (MPO) methods had a common major drawback – they calculated par scores and revised targets solely on the basis of run rate and overs, not taking wickets into consideration. DLS method, on the contrary, includes both overs left and wickets remaining in the calculation.
The basic principle of the calculation is – Resource. Every team is allocated two sets of resources, that is, wickets and overs. However, these resources are not calculated in their holistic, integer form – they are converted into percentages according to their specific weightage.
Understanding DLS With an Example
Let us simplify things for you with an example – the India vs Bangladesh match at the ICC Men’s T20 World Cup 2022. India batted first and scored 185/6 in their allotted 20 overs.
When Bangladesh came out to bat, they had both 20 overs to face, and all 10 wickets in hand, which translates to 100% of their available resources. With every delivery and every wicket, a team’s resource gets depleted, and accordingly, the par score is calculated.
The match was interrupted by rain after seven overs, when Bangladesh were batting at 66/0.
The formula used in calculating par score according to the DLS method looks like this:
Bangladesh’s Par Score = India’s Final Score * (Resources Utilised by Bangladesh ÷ Resources Utilised by India)
Since India batted first and had no interruptions to deal with, resources utilised by India would be 100%, making the equation look like this:
Bangladesh’s Par Score = India’s Final Score * Resources Utilised By Bangladesh
Given below is the official DLS over-by-over par scores table for the India vs Bangladesh fixture.
According to the DLS calculation, when Bangladesh were 66/0 after seven overs, they utilised about 27% of their available resources. So the calculation would have been: Bangladesh’s par score = 184 * 27% (approx), which comes to around 49.
The loss of wickets is directly proportional to the loss of resources. Hence, had Bangladesh lost four wickets in the first seven overs, the par score would then have been 74.
Importantly, it should also be understood that matching the DLS par score would only mean the scores are tied – the team batting second needs to score an extra run to confirm victory. South Africa’s Mark Boucher had once failed to comprehend this during a 2003 World Cup game against Sri Lanka, which resulted in his team drawing the match instead of what should have been a comfortable victory.
In occasions where a game resumes after an interruption, like the one between India and Bangladesh, the revised target of the team batting second is proportional to the resources depleted from that team’s arsenal.