DUCKWORTH-LEWIS METHOD

1.INTRODUCTION

The Professional Edition of the Duckworth-Lewis method shall be used in all matches. If any match is suspended after it has started such that the number of overs available to be faced by either side is reduced from that determined when the match started, the revised target shall be computed using the latest version of the ‘ICC Duckworth/Lewis Calculator’ as distributed by ICC in accordance with the instructions provided with that software.

These are not in direct proportion to the number of overs available to be faced, as with the average run rate method of correction. Instead they depend on how many overs are to go and how many wickets are down when the interruptions occur

The number of these extra runs required is calculated by applying the excess resource percentage to the average total score in a 50-over innings, referred to here as G50.

*For matches involving ICC full member nations, or for matches between teams that play first class cricket, the value of G50 should be 245.

For lower levels of the game:

• under 19 international matches

• under 15 international matches

• women’s international matches

• matches between associate ICC member nations

the value of G50 should be 200.

2 .DEFINING TERMS

• The team batting first are referred to as ‘Team 1’ and the team batting second are referred to as ‘Team 2’.

• In the table decimal fractions of an over are expressed in standard cricket notation; i.e. 4.3 overs means 4 overs plus 3 balls.

• The terms ‘target’ and ‘revised target’ are reserved exclusively for the minimum score Team 2 need to win.

• As with an uninterrupted match, if Team 2 make a score which is one run short of the target, the match is tied.

The following symbols are used throughout:

N is the number of overs per innings for the match as decided at the moment of delivery of the first ball of the match.

S is Team 1’s total score.

R1 is the resource percentage (relative to a full 50-over innings) available to Team 1.

R2 is the resource percentage (relative to a full 50-over innings) available to Team 2.

T is Team 2’s target score.

3 .CALCULATION OF PERCENTAGE, WHEN SUSPENSION OCCURS

To compensate for any loss of overs due to a suspension in play during either Team 1’s or Team 2’s innings, it is necessary first to calculate the resource percentage that has been lost on account of this suspension.If the suspension occurs between overs, use the sheet of the table which gives the figures for whole numbers of overs. If it occurs mid-over, use the sheets of the table which provide the figures for each individual ball.

3.1 For the start of the suspension in play, from the table note the resource percentage that remained for the appropriate number of overs/balls left and wickets lost.

3.2 For the resumption of play after the suspension, from the table note the resource percentage now remaining for the revised number of overs/balls left and for the same number of wickets lost.

3.3 Subtract the resource percentage in 3.2 from that in 3.1 to give the resource percentage lost.

3.4 If a suspension in play causes the innings to be terminated, the resource percentage on resumption (3.2) is zero and the percentage lost is the resource percentage which was remaining when the suspension occurred (3.1).

3.5 If more than one suspension in play occurs, the resource percentages lost are calculated as described in 3.1 to 3.4 and are accumulated to give updated values for the total resource percentage lost or resource available for the innings. This is done after each suspension as described in 5.2 and 5.5.

4.PENALTY FOR SLOW OVER RATE

No overs penalties are imposed for slow over rates and hence slow over rates have no effect on revised target calculations.

5.CALCULATION FOR REVISED TARGET

5.1 Note the number of overs per innings decided at the start of the game,

N. From the table note the resource percentage available to Team 1 at the start of their innings.

(For N = 50 this is 100%.)

5.2 For all suspensions and any premature termination of Team 1’s innings, calculate the total resource percentage lost using the procedure described in section 3. Subtract this from the starting resource percentage (5.1) to give R1, the resource which was available to Team 1 for their innings. Note Team 1’s total score, S.

5.3 There is no overs penalty for slow over rates by either side.

5.4 Note the number of overs allocated to Team 2 at the start of their innings and from the table note the resource percentage for this number of overs remaining and 0 wicket lost. This is R2, the resource percentage available to Team 2. If R2 differs from R1, which will happen if Team 1’s innings was interrupted and/or Team 2’s was delayed, a revised target must be set. Calculate this revised target, T, as described in 5.6 below.

5.5 For each suspension of play during Team 2’s innings or for premature termination of the match, update the resource percentage available, R2, by subtracting the resource percentage lost calculated as in section 3. Calculate the revised target, T, after each suspension as described in 5.6 below. If the match has to be terminated, the result is decided by comparing Team 2’s score at the time with the ‘par score’, this being the value as calculated in the formulae for T in 5.6 below, but without the one run added. If it is greater, Team 2 win. If it is equal, the match is tied. If it is less,

Team 1 win.

5.6 If R2 is less than R1, Team 2’s revised target is obtained by reducing Team 1’s score S in the ratio of R2 to R1, ignoring any figures after the decimal point, and adding one run

i.e. T = (S x R2/R1) + 1 (rounded down to a whole number, if necessary).

If R2 is equal to R1, no revision is needed and Team 2’s target is one more run than Team 1’s score.

i.e. T = S + 1

If R2 is greater than R1, calculate the amount of excess resources, R2 – R1, and take this percentage of the average 50-over total, G50, to give the extra runs needed, ignoring any figures after the decimal point.

i.e. T = S + (R2 – R1) x G50/100 + 1 (rounded down to a whole number, if necessary)

6. EXAMPLES OF RESULT DESCRIPTION

i Team 2 are set a revised target of 186. But they only succeed in making 180 in their allocation of overs. They thus fall 5 runs short of the 185 runs needed to tie the match and the result is described as ‘Team 1 win by 5 runs (D/L method)’.

ii Team 2 are chasing a target of 201 in a 50-over per innings match and reach 105/4 after 25 overs when rain causes the match to be abandoned. At this point the ‘par score’ is 100. Team 2 have exceeded this by 5 runs and so the result is described as ‘Team 2 win by 5 runs (D/L method)’.

Example 1 (Suspension during Team 1’s innings)

In a 50 over-per-innings match, Team 1 reaches 79/3 after 20 overs and then there is a suspension in play. It is decided that 20 overs of the match should be lost, 10 of these by each team. Team 1 resumes to reach a final total of 180 in its revised allocation of 40 overs.

Number of overs per innings at the start of match, N = 50

Resource percentage available to Team 1 at start of innings = 100% (5.1)

Resource percentage remaining at suspension (30 overs left, 3 wkts lost = 61.6% (3.1)

Resource percentage remaining at resumption (20 overs left, 3 wkts lost) = 49.1% (3.2)

Resource percentage lost due to suspension = 61.6 – 49.1 = 12.5% (3.3)

Resource percentage available to Team 1, R1 = 100 – 12.5 = 87.5% (5.2)

Number of overs available to Team 2 at the start of its innings = 40

Resource percentage available (40 overs left, 0 wkt lost), R2 = 89.3% (5.4)

R2 is greater than R1, i.e. Team 2 has more resource available than had Team 1, so its target should be increased. S = 180

Team 2’s revised target (5.6) is

T = S + G50 x (R2 – R1)/100 + 1 = 180 + 245 x (89.3 – 87.5)/100 + 1 = 185 (rounded down).

Example 2 (suspension during Team 2’s innings)

In an One Day International match (50 overs per innings), Team 1 has scored 250 from its allocation of 50 overs in an uninterrupted innings. Team 2 has received 12 overs and has scored 40/1. Then play is suspended and 10 overs are lost.

Number of overs at start of match, N = 50.

Team 1’s innings was uninterrupted, so its resource percentage available, R1 = 100% (5.1).

Resource percentage available to Team 2 at start of innings = 100% (5.4).

Resource percentage remaining at suspension (38 overs left, 1 wkt lost) = 82.0% (3.1).

Resource percentage remaining at resumption (28 overs left, 1 wkt lost) = 68.8% (3.2).

Resource percentage lost due to suspension = 82.0 – 68.8 = 13.2% (3.3).

Resource percentage available to Team 2, R2 = 100 – 13.2 = 86.8% (5.5).

R2 is less than R1; S = 250.

Team 2’s revised target (5.6) is

T = S x R2/R1 + 1 = 250 x 86.8/100 + 1 = 218 , and it needs a further 178 runs from 28 overs.