What is the Duckworth Lewis Stern (DLS) Method in Cricket?

The Duckworth Lewis (DLS) method in Cricket, now known as the Duckworth-Lewis-Stern Method is a mathematical formula devised to calculate the target score for a team batting in the second innings in a cricket match interrupted by bad weather. Two English statisticians namely, Frank Duckworth and Tony Lewis devised the formula and it was used for the first time in the year 1997 in the second match of the Zimbabwe versus England ODI series.

It was in November, 2014 ahead of the 2015 ODI World Cup when Australian Academic Steve Stern made some modifications in the method, thus, becoming its custodian and getting his name added to the mathematical expression as well. Let’s learn more about DLS Method in Cricket.

Duckworth and Lewis felt the need for a way to determine target score in an interrupted cricket match post the injustice that took place in the semi-final of the 1992 ODI World Cup where South Africa, playing against England, required 22 runs in 13 balls to win, the equation which after a villainous cameo by the rain gods, went on to be 21 runs needed off 1 ball.

This was done following the ‘Most Productive Overs’ method. Frank Duckworth recalled hearing the commentator for the match Christopher Martin Jenkins claiming, ‘Surely someone, somewhere can come up with something better.’ and that is exactly what he did along with Tony Lewis.

How does the DLS Method in Cricket works?

The DLS Method is a statistical attempt to set a target for the team batting second in a rain-interrupted match which is of the same difficulty as the original goal. The basic principle of the formula being the wickets in hand and the overs left, both of which are the resources of the batting side to chase down the target.

At the start of the innings, the batting side has 100% of its resources and as the match goes on with overs being bowled and wickets falling, the resources start to deplete. The DLS method, after taking into account the percentage figures of the two resources, lays out all possible combinations of balls left and wickets in hand into a Combined Resources Remaining percentage figure.

The target score for the team batting second can be adjusted up or down from the total the team batting first achieved using these resource percentages. A par score can also be calculated to decide the winner of the match in case the match cannot be resumed after the interruption.

The worth of a wicket or a ball in percentage terms is calculated according to a formula, taking into account the scoring pattern in international matches which is derived from the analysis of data in ODI and T20 matches, separately for men’s and women’s cricket from a sliding 4-year window and on 1st July every year, the new year’s worth of data is added.

The DLS Method in cricket which is most commonly used in international and first-class matches around the globe can be expressed in the following way:

If the par score for the team batting second comes out to be a non-integer, it would be rounded-off to the next integer value to find out the winning target and the par score would be rounded down to the preceding integer to find out the tie score. For instance, if 228.5 comes out to be the par score for the team batting in the second innings of the match, their winning target would be 229 runs and the match would be a tie if they score 228 runs.

Criticism of the DLS Method Cricket

Along with massive acclaim for providing solutions to a very important problem of the sport, the DLS Method also received criticism regarding some key provisions of the method. One such criticism of the method was that it could not distinguish between or put different weightage to balls left and wickets in hand according to the match situation.

Wickets in hand can prove to be more useful for the chasing side in a lot of cases than balls left, especially if chasing down a low first innings score. A provision was made in the method in the year 2014 when its name was changed from D/L method to DLS method and the new rule changed the rate at which teams needed to score at the start of the second innings in response to the first innings total.

Another key criticism of the method is that it does not account for the changes in the durations of the innings where field restrictions are in place as field restrictions cause considerable difference in the run rate of the batting side.

The criticisers of the rule have not only termed it as unduly complex but they also claim that the rules can easily be misunderstood by players, support staff and also the fans, making the sport lose the hold it has.

Concerns have also been raised as to its suitability for Twenty20 matches, where a high scoring over can drastically alter the situation of the game, and variability of the run-rate is higher over matches with a shorter number of overs.

Do we have an alternative of DLS method in Cricket?

The existing DLS method even with its flaws is a system which gets the stakeholders of the game closest to what they deserve in a rain-interrupted match, that is, a result. With minor tweaks in the methodology such as taking into account the duration of the innings when field restrictions are in place and adjusting the formula accordingly can go a long way in increasing the efficiency of the results.

Even if the prayers of all fans of the sport to not let a match be interrupted by rain still echo in fear of an unjust conclusion, the DLS method is the way to get the closest to an honorable decision of a cricket match.