Duckworth-Lewis

The Duckworth-Lewis update

Frank Duckworth and Tony Lewis, inventors of the now well-known system of resetting targets in interrupted matches that bears their names, have announced an update to their tables. This follows an extensive analysis of limited overs cricket matches in recent years that they have undertaken. "The nature of the one-day game is changing," said Duckworth "and our tables need to reflect developments in playing strategies". These changes come into effect for competitions starting on or after 1st September. And they have already been used for the tour match between the 'A' teams of South Africa and Australia on 4th September.

There will be no change to the way that the well-established D/L method works, which is described in published books and summarised on the Cricinfo webpage. Lewis said that the effects of the new tables "will in most cases be to lower slightly the enhanced targets when the first innings is interrupted and to raise slightly the D/L par scores during the early part of the reply".

Duckworth and Lewis felt that it was in the interests of the game that the D/L method should be stable whilst the world got used to it. "The time is now ripe to reflect recent advances in the game" they said.

Here is an extract of the new tables

	Wickets lost
Overs left	0	2	5	7	9
50	100	85.1	49	22	4.7
40	89.3	77.8	47.6	22	4.7
30	75.1	67.3	44.7	21.8	4.7
25	66.5	60.5	42.2	21.6	4.7
20	56.6	52.4	38.6	21.2	4.7
10	32.1	30.8	26.1	17.9	4.7
5	17.2	16.8	15.4	12.5	4.6

Effects of the new tables
The examples that Duckworth and Lewis use to explain their method are now reworked using these new tables

Example 1: Premature curtailment of Team 2's innings Team 1 have scored 250 runs from their 50 available overs and Team 2 lose 5 wickets in scoring 199 runs in 40 overs. Play is then stopped by the weather, the rain refuses to relent and the match is abandoned. A decision on the winner is required.

Team 1's innings: this was uninterrupted, so the resource percentage available is	100%
Team 2's innings: resource % available at start of innings =	100%
After 40 overs Team 2 have 10 overs left and have lost 5 wickets. From table, resource % left at suspension of play =	26.1%
As play is abandoned all this remaining resource is lost. Hence resource % available for Team 2's innings = 100 - 26.1 =	73.9%

Team 2 had less resource available than Team 1 and so to give the target Team 1's score must be scaled down by the ratio of resources, 73.9/100.
Team 1 scored 250, so Team 2's 'target' is 250 x 73.9/100 = 184.75. The next lower whole number, 184, is the score to tie, or the 'par score' for the match situation at the stoppage.As there is to be no further play, the winner is decided according to whether or not the par score has been exceeded. With 199 runs on the board, they have exceeded this by 15 and so are declared the winners by 15 runs.