Is DUCKWORTH-LEWIS method easy to understand ????

When i was watching the match between England and India,suddenly i came to know about D/L method.In that match,India batted first but rain played the spoilsport.However after rain has finished its game
India played from 17th over and the match was reduced to 22 overs a side.India scored 166/4 in 22 overs and England needed 198 runs to win in 22 overs.This announcement made by using D/L method.I am writing this to explain D/L method but if u are still cant understand i am sorry that it is confusing me too.


ORIGIN :

This method, devised by Frank Duckworth and Tony Lewis,is a mathematical way of calculating the target score in an ODI or T20 interrupted by any cause.

RULES FOR APPLYING THIS METHOD :

Each team has to face atleast 20 overs in ODI or 5 overs in T20.Then only this method can be applied.

This method depends on two resources.They are 1) The number of overs a team received 2) The number of wickets they had in their hands.

FORMULA TO CALCULATE THE PERCENTAGE :

Z(u,w) = Z0(w)[1-exp{-b(w)u}]


Z(u,w) -----> Expected number of runs to be scored in u overs when w wickets have been lost.

Z0(w) -----> Average total score if an unlimited number of overs overs were available and when w wickets have been lost.

b(w) -----> Decay constant that varies with w,the number of wickets lost.


This formula cant be used without using computers.The software used to calculate this method is CODA ,which is used by ICC officials and has not been released by the governing body to the public domain.

Table 1: Extract from the table of resource percentages remaining

	Wickets lost
Overs left	0	2	5	7	9
50	100.0	83.8	49.5	26.5	7.6
40	90.3	77.6	48.3	26.4	7.6
30	77.1	68.2	45.7	26.2	7.6
25	68.7	61.8	43.4	25.9	7.6
20	58.9	54.0	40.0	25.2	7.6
10	34.1	32.5	27.5	20.6	7.5
5	18.4	17.9	16.4	14.0	7.0

Reading the table

The single table applies to all lengths of one-day matches from 50 overs-per-side downwards. Because this length of match is by far the most common, the resources listed in the table are expressed as percentages of those available at the start of a 50-over innings. Thus when there are 50 overs still to be received and no wickets have been lost, the resource percentage available is 100%. A 40-over innings starts with a resource percentage of 90.3% relative to a 50 over innings. An innings shortened to 25-overs before it starts commences with a resource percentage of 68.7% relative to 50-over innings. (Although such innings have only half the overs of a 50-over innings they have all 10 wickets and so have much more than half the resources.)

In order to determine the correct resource percentage the batting side has remaining at any stage of its innings, the number of overs left must be identified. This number of overs left, in conjunction with the number of wickets lost, is then used to read the resource percentage remaining from the table.

For example, suppose that after 20 out of 50 overs a team have lost 2 wickets. They have 30 overs left. From the table you will see that the resource percentage remaining is 68.2%.

Suppose now that there is an interruption in play and 10 overs are lost from the innings. When play can resume there are only 20 overs left but there are still, of course, 2 wickets down, and the table now tells us that the resource percentage remaining is 54.0%. Thus the shortening of the innings has caused the team to lose a resource percentage of 68.2 - 54.0 = 14.2%.

Having started with a resource percentage of 100% and lost 14.2%, then if they complete their innings with no further loss of overs, they will have had a resource percentage available for their innings of 100 - 14.2 = 85.8%.

So simple , isn’t it ?????