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It’s the most popular system of its kind, but it’s also attracted its fair share of controversy over the years. It’s time to take a closer look at the Duckworth Lewis Method.
What is DLS Method in Cricket?
The Duckworth Lewis Method is a system used to determine targets and results in cricket matches which have been shortened due to bad weather.
With its two founders having retired, the custodian of the method is Professor Steven Stern. As a result, the system should now be referred to as Duckworth Lewis Stern.
Using DLS Calculation – How Does it Work?
DLS is used to set a target for the team batting second in a rain affected match. It uses calculations based on the number of overs remaining and the number of wickets that the batting team has in hand.
It can be extremely complicated from this point and an in-depth understanding of mathematics certainly helps. Essentially, there is a table set in place which determines the target, based on a factor known as resource percentage.
That resource percentage starts at 100% when a team has 50 overs left to bat and all ten wickets still in hand. As the innings progresses and wickets and overs are lost, the percentage diminishes.
For example, with 40 overs left and two wickets lost, the resource percentage drops to 77.6%. That percentage is then used to calculate a revised target.
Note that the DLS target can be fluid during an innings. If rain or bad light stops play completely at a certain point, there will be a DLS par score. The batting side have to exceed that score in order to win the game.
History of the Duckworth Lewis Method
Scoring methods had been used to recalculate run rates for some time. However, none of these were particularly effective and, in the 1992 World Cup in Australia, they produced a farcical finish to one match.
South Africa were famously closing in on a target set by England until rain intervened. Under the old system, the South Africans were left needing 21 runs from one ball when the players returned.
Change was needed and the original D/L method was devised by two British statisticians, Frank Duckworth and Tony Lewis. Their method addressed issues with previous systems.
Duckworth Lewis was first used in a One Day International between Zimbabwe and England on January 1st, 1997. In 1999, it was formally adopted by the International Cricket Council (ICC) as their standard method for calculating results in weather affected matches.
Remember that you need to be at least one ahead of the Duckworth Lewis Method in order to win the game in question. South Africa famously forgot this point in the ODI World Cup which was held in their own country in 2003.
In a rain affected game against Sri Lanka, Mark Boucher hit a six to bring the teams level on D/L. There was time for one more ball before the match was abandoned. Thinking that he’d done enough, Boucher blocked the delivery, but he actually needed at least a single. The game was called off and South Africa lost.
There are many other instances where Duckworth Lewis has been used in less dramatic circumstances.
In the first ODI of a series between Indian and Pakistan in 2006, India had completed their innings and had posted 328. Pakistan replied and had reached 311/7 when bad light stopped play in the 47th over.
Had they been able to continue, Pakistan would have needed 18 runs from 18 balls to win the game. The teams were unable to return to the field and Duckworth Lewis worked out that the revised target at the point the match was interrupted would have been 305.
Pakistan therefore won this game by seven runs under D/L.
Duckworth Lewis can be brought into play at any point in a match. If rain interrupts during the first innings, a reduction in overs will be applied. Sri Lanka hosted England in an ODI in December 2014. Sri Lanka batted first and had made 6/1 from two overs when rain came.
The match was restarted but it was reduced to 35 overs a side. Sri Lanka eventually posted 242/8, but D/L adjusted England’s target to 236. Because rain had affected part of the game, Duckworth Lewis was required with a view to make things fairer.
It’s necessary to have a method such as Duckworth Lewis Stern in order to decide games. It is, however, tricky to describe these systems and I feel that you need an advanced knowledge of maths in order to fully understand how they work.
When I’m at a game, I tend to follow the scoreboard to check the D/L par score and I trust that the calculations are working.
It’s also interesting to compare this with the VJD method which I’ve discussed in a separate article. Is it right to continue with Duckworth Lewis or is there a better way to settle games that have been affected by the weather?
There will be differences of opinion on that matter. Duckworth Lewis Stern has its critics, but it is the preferred method of the ICC right now and it’s the one that we’ll see in the vast majority of matches.
One thing we can surely all agree on is the fact that this is a better option than what we had in place before. South Africa’s revised target at the 1992 World Cup was a ridiculous one and DLS has certainly made things fairer since its introduction.