What is DL-Method or DLS-Method in Cricket?

We as cricket fans feel very frustrated whenever rain interrupts the match. No matter whether we are in the stadium, whether we are at our home, whether we are at office or whether we are at a local tea stall somewhere around the back doors of a locality.

The iconic Lord's Cricket Ground under the covers due to rain.

There are so many matches in the past which got washed out due to rain and every one of us have suffered. ICC – International Cricket Council has made some adjustments for the above matter. There is a provision for this rule that when a match is halted by the rain or forced to stop in between, some adjustments are made to the runs and the overs in proportion to the time left in the game. It is important to note that this rule/method can only be applied if the match is possible to be played further on the field.

This is called DL-Method. This method is officially adopted by the ICC since 1999. DL-Method is named after two statisticians, Frank Duckworth and Tony Lewis (Duckworth-Lewis Method). An amendment in the name was made later, which is now DLS-Method - Duckworth-Lewis-stern method. This method helps to adjust the target for the team batting second in the limited overs matches. It does so by some mathematical calculations & deducting the overs from their quota and deducting the runs from the target which was earlier set by the team batting first before the rain intervention. It is not a simplified version as to just deduct the overs and the runs according to the time lost. Instead, there are lot of factors involved for adjusting target by DL-Method.

There are two major possible instances when the DL-Method could be applied:

Instance 1

There may be the possibility of rain even before the match is started. In such a case, the deduction of overs is applied to both the innings where the teams could be given the chance of batting certain reduced number of overs as pre-decided by the DL-Method. This reduction of overs does not affect the target for team batting second, unless there is another rain interruption after the match is started.

For example, there are two teams playing a match; Team A – batting first, Team B – batting second.

The match is shortened to 35 overs per side due to rain. Team A has started their innings and played out 25 overs and suddenly there is another rain delay. So, there will be deduction of overs by DL-Method. Imagine that the overs are reduced to 30 overs per side now. Hence, this will lead to an interesting calculation here. When Team A finish their innings and they set the target for Team B, Team B might have to chase few more runs than what is originally set by Team A. This is because Team A started their innings before the second rain interruption and at that time, they only knew that they have 35 overs to play. Hence, Team A would have scored more aggressively had they known that they have only 30 overs. So, to balance the game, DL-Method adjusts the runs which Team A could not score because of the deduction of their 5 overs which they thought they would be playing before second rain break. So, this way Team B might be chasing more runs than what was actually scored by Team A.

The Umpires discussing about restarting the match after a rain interruption.

Instance 2

Team A – batting first, Team B – batting second.

Sometimes, it may be possible that Team A has batted out their full 50 overs without any stoppage. But the rain arrived during innings break, and the DL-Method is applied. After making some mathematical calculations, Team B receives their revised target. There is a term “Par score” also comes into picture if there is intermittent rain. The Par score is the required score at any instance of the innings for Team B in case no more play is possible further due to rain on that instance. The Par score keeps changing according to the runs scored and wickets left. The Par score must be applied only if Team B have at least played out 20 overs from their quota. If the overs are reduced to less than 20 then the Team B must have at least played out 6 Overs from their quota, no result is possible otherwise.

The players walking off as the match was stopped due to rain.

The calculation plays a vital role in this; takes into consideration the pace of the game by both the teams.

How the calculations are made by DL-Method or DLS-Method?

For any team, there are two things helpful to score the runs; No of overs left & No of wickets in hand. These two combined are called “Stock”. The stock is said to have 100% when any team have 50 overs and 10 Wickets remaining in their innings. This stock is changed according to the situations based on how a team normally bats in the similar situation and how their regular scoring rate is. There are some mathematical calculations taken into consideration from hundreds of limited overs matches from the history and the data is derived. Below is the equation how to calculate the par score:

For example, if Team A’s total score is 260 from 50 overs, means they have used their 100% stock, and Team B have 60% stock remaining due to reduction by DL-Method. In this case, when we put these values in the equation; 

 

So, calculating by this equation, the Par score (The Target) will be 156 for Team B.

The advanced calculations are not possible manually. There is a computer available with this software loaded, which provides the full table for ball by ball information of the stocks available for any team. The data that this software calculates includes the approach of a team during a particular phase of the innings, the types of the batsmen they have available to bat next and the types of the bowlers remaining to bowl their overs. This information is not available publicly due to commercial reasons.

This is how the score is balanced for Team batting second in a rain affected game. This method has its some own advantages and disadvantages, but it is what official as of now in limited overs cricket.

 

Thanks

Rahul