Duckworth- Lewis Method
We are seeing many matches being washed out and using a method to revise targets. The method used to revise the target is called Duckworth-Lewis Method or DL method.
What is Duckworth- Lewis method??
Duckworth-Lewis method is a formula used in limited over’s matches which are affected by rain or are temporarily stopped because of any other reason. It uses the over’s reaming and wickets in hand to estimate the total of a team.
The traditional method used up to 1997 to revise targets when weather interfered with limited-overs cricket was based on average run-rate. The only advantage of such a system was that it was easy to understand and calculate for all concerned - players, officials and spectators - but it almost always gave a hugely unfair advantage to the team batting second, with the result that captains winning the toss when rain was around almost always chose to field first.
From 1997, the ECB adopted the Duckworth/Lewis method as a fairer system, since then the ICC has done likewise. Before the days of D/L, there were some horrific examples of the average run-rate method producing ridiculous situations - today there are few. D/L is now generally accepted by players who understand it as by far the fairest method yet devised for target resetting.
To avoid the spectacle of the batsmen meeting in mid-wicket and consulting Duckworth/Lewis tables and pocket calculators between every over, the scorers and match manager generally do the calculations and display the difference between the runs achieved and the score needed to win - if the match were to be finished at that instant - as a figure on the scoreboard, so all can see whether the batting side are ahead of or behind the target.
Frank Duckworth & Tony Lewis were professional statisticians and mathematicians who worked closely with the ECB. They have done extensive research into past limited overs cricket matches, updating and improving their own system over the last 5 years.
In simple terms, the D/L system converts the number of overs remaining and the number of wickets lost into a "resources remaining" figure. As overs are completed or wickets fall - the "resources remaining" falls.
D/L has far fewer anomalies than any previous method. Whenever rain interrupts a match, the D/L method is designed to leave the balance of the match unaltered.
Where other earlier methods crucially overlooked the importance of wickets lost at the point of delay, the D/L method incorporates this factor into its calculation. It is obviously much easier to chase 100 runs with ten wickets left than with just three wickets standing and the D/L method was the first of its kind to recognise this.
The adjustments that the D/L method makes try to ensure that after a rain break, the status quo of the match is roughly retained. If the 'chasing' side is ahead when rain arrives, then they are awarded the match if no further play is possible. This has given rise to a whole new tactical approach for teams batting second.
Although the D/L method consistently spits out fair equations, which are easily understandable, its more intricate formulae are highly complicated and far too difficult for the ordinary man to comprehend. However, players and spectators do not need to bother themselves with more than a grasp of how the system operates and how it might affect tactics in any one-day match.
The D/L method has been criticized on the grounds that wickets are a much more heavily weighted resource than overs, leading to the suggestion that if teams are chasing big targets, and there is the prospect of rain, a winning strategy could be to not lose wickets and score at what would seem to be a "losing" rate (e.g. if the required rate was 6.1, it could be enough to score at 4.75 an over for the first 20–25 overs). The 2015 update to D/L/S recognised this weakness and changed the rate at which teams needed to score at the start of the second innings in response to a large first innings.
Another criticism is that the D/L method does not account for changes in proportion of the innings for which field restrictions are in place compared to a completed match.
More common informal criticism from cricket fans and journalists of the D/L method is that it is unduly complex and can be misunderstood. For example, in a one-day match against England on 20 March 2009, the West Indies coach (John Dyson) called his players in for bad light, believing that his team would win by one run under the D/L method, but not realizing that the loss of a wicket with the last ball had altered the Duckworth–Lewis score. In fact Javagal Srinath, the match referee, confirmed that the West Indies were two runs short of their target, giving the victory to England.
Team batting second's par score=
Team batting first's score X (team batting second's resources/team batting first's resources)
Resources are given by
Total resources available = 100% − Resources lost by 1st interruption − Resources lost by 2nd interruption − Resources lost by 3rd interruption −...