Duckworth-Lewis-Stern(DLS) Method in cricket full details

The DLS Method (Duckworth-Lewis-Stern Method) is a mathematical formula used in cricket to calculate revised targets for interrupted matches, such as those affected by rain, bad light, or other delays. It ensures a fair outcome when a limited-overs match cannot be completed as originally scheduled.

Key Details and Explanation:

1. Objective:
   • The DLS method adjusts the target score in a way that accounts for both the overs left and the number of wickets lost. It aims to balance the advantage for both teams in an interrupted match.
2. History:
   • The method was developed by two British statisticians, Frank Duckworth and Tony Lewis, in 1997.
   • Steven Stern later updated and refined the method, and it became known as the Duckworth-Lewis-Stern (DLS) method in 2014.
3. How It Works:
   • Resources Concept: The method is based on the idea that a team’s ability to score runs depends on two resources:
     • Overs Remaining: How many overs are left to bat.
     • Wickets in Hand: How many wickets are left.
   • A resource table is used, which calculates the percentage of resources available to a team at any given point in the match.
   • In case of interruptions, the DLS method calculates the revised target by comparing the resources available to both teams.
4. When It Is Used:
   • Rain-affected matches where one or both innings are shortened.
   • Multiple interruptions during a match.
   • Second innings adjustments, if interruptions occur during the chasing team’s innings.
5. Key Features:
   • The revised target is fairer than previous methods like the Average Run Rate, which didn’t consider wickets in hand.
   • It dynamically adjusts based on game scenarios (e.g., a team with more wickets in hand has a greater capacity to score quickly).
6. Example Scenario:
   • Team A scores 300 runs in 50 overs.
   • Team B is chasing but rain interrupts play after 25 overs, with Team B at 150/3.
   • Using the DLS method, the target is recalculated based on the remaining overs and wickets lost, ensuring fairness.
7. Practical Use:
   • The DLS method is widely used in all international limited-overs matches, including ODIs and T20Is, and in domestic tournaments.

Advantages:

• Considers both overs and wickets for fairness.
• Works well for matches with complex interruptions.

Criticism:

• May be difficult for casual viewers to understand due to its mathematical nature.

Key Concept: Resource Percentage

The DLS system uses a Resource Percentage Table that quantifies how much of the total scoring potential remains at any point in the match. The total resources at the start of an innings are 100%.

For example:

• A team with 50 overs left and all 10 wickets has 100% resources.
• A team with 20 overs left and 5 wickets has far fewer resources.

Steps in DLS Calculation

1. Estimate Available Resources: At every interruption, the resources available to each team are calculated from the table based on overs remaining and wickets in hand.
2. Calculate the Adjusted Target: Using the resources, the target for the second team is adjusted proportionally.
3. Adjust for Interruptions During the Second Innings: If rain interrupts the second innings, the remaining resources for the chasing team are calculated, and the target is revised accordingly.

Example Calculation

Scenario:

• Match Type: ODI (50 overs per side)
• Team A’s Score: 250 runs in 50 overs.
• Team B’s Target: Initially 251.
• Rain Interruption: After 30 overs of Team B’s innings, rain reduces the match to 40 overs. Team B is 150/3 at this point.

Step 1: Resources Available

1. Team A’s Total Resources:
   • Started with 50 overs, so they used 100% resources.
2. Team B’s Resources:
   • Originally had 50 overs, but now reduced to 40 overs.
   • From the resource table:
     • At the start of their innings, 40 overs with 10 wickets is 89.3% resources.
     • After 30 overs with 7 wickets in hand, the remaining resources are 25.5%.

   Resources used by Team B so far = 89.3% – 25.5% = 63.8% resources used.

If the Match Ends Early

If rain prevents further play, the team that has scored above the par score when play stops is declared the winner. If the score is below, the opposing team wins.

Summary of DLS Method Steps

1. Identify the resources for both teams from the resource table.
2. Calculate the par score or adjusted target using the formula.
3. Consider interruptions and dynamically adjust based on wickets and overs left.

This ensures that both teams are treated fairly, regardless of match interruptions.