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
Effects of the 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
Example 2: Interruption
to Team 2's innings
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, 78.6/89.3 Team 1 scored 200, so Team 2's 'target' is 200 x 78.6/89.3 =176.04 which rounds down to 176 to tie with a revised target of 177. They then require a further 37 runs to win from 5 overs with 5 wickets in hand.
Example 3: Interruption to Team 1's innings
Because of the different stages of the teams' innings that their 10 overs are lost, they represent different losses of resource. Team 1 have lost 7 wickets and had 10 overs left when the rain arrived and so from the table you will see that the premature termination of their innings has deprived them of the 17.9% resource percentage they had remaining. Having started with 100% they have used 100 - 17.9 = 82.1%; in other words they have had 82.1% resources available for their innings.
Team 2 will also receive 40 overs. With 40 overs left and no wicket lost you will see from the table that the resource percentage which they have available (relative to a full 50 over innings) is 89.3%. Team 2 thus have 89.3 - 82.1 = 7.2% greater resource than had Team 1 and so they are set a target which is enhanced by 7.2% of 235, or 16.92, more runs than Team 1 scored. [235 is the revised average in 50 overs for ODIs in recent years].
Using the sum 190 + 16.92 = 206.92, rounding down gives 206 to tie and Team 2's target is 207 in 40 overs.
Note: Most other target resetting methods previously used would make no allowance for this interruption. They set the target of 191 simply because both teams are to receive the same number of overs. This is clearly an injustice to Team 1 who were pacing their innings to last 50 overs when it was curtailed, whereas Team 2 knew in advance of the reduction of their innings to 40 overs and have been handed an unfair advantage. D/L neutralises this by setting Team 2 an enhanced target over the number of runs Team 1 actually scored.
The computer program CODA, which carries out all calculations of D/L targets and provides many features besides, has also been updated. Arrangements for obtaining this program have now changed. These will be advised on this website in due course. Existing owners of CODA should email Tony Lewis as below requesting information on how to update their copy.
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