Duckworth-Lewis Method

[Ahmed]

Below is a description of the Duckworth-Lewis method used in World Cups for determining revised targets for rain-hit matches. Pretty simple, isn't it?
Couldn't they have simply used socring averages instead of counting "scoring resources"? Don't think it would be that much of a difference at the end.

What do you guys think? IS the duckworth-lewis a good method or not? What advantages or disadvantages does it have?


ICC Media Information: Duckworth/Lewis calculations explained
ICC Media Release - 16 February 2003
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Below follows a basic summary of the Duckworth/Lewis method for recalculating totals in rain-interrupted matches.

Further details of the calculations plus examples are available on the ICC Cricket World Cup Media Information System.

Summary:


- The D/L method sets a revised target for the side batting second (Team 2) when overs have been lost by a suspension in play. The revision is not in proportion to the numbers of overs the two sides can receive but is in accordance with the run-scoring resources the two sides have at their disposal. These resources include both overs and wickets in combination.

- A single table gives the resources remaining at any stage of an innings for any number of overs left and wickets lost. The resources are expressed in terms of the percentages of the resources of a full 50-over innings.

- If either innings is shortened after it has started then the balance of resources of the two sides is upset and a revised target needs to be set in accordance with the resources available to the two sides. To find the resources available for either innings, you use the table to find out the resources lost from that innings and subtract this from the resources with which the innings started. If the innings started with 50 overs to be received, the resources at the start of the innings are 100%. But if the innings is shortened before it starts, or if the match is of less than 50 overs per side, then the resources at the start are less than 100%.

- To find the resources lost from an innings due to an interruption:
(i) note the numbers of overs left and wickets lost at the start of the suspension; use the table to find the resources remaining

(ii) note the same at the resumption of play and from the table read off the resources now remaining

(iii) subtract (ii) from (i) to give the resources lost.


- To find the resources available subtract the resources lost from the resources that were available when the innings started.

- When a revised target has to be set, find the resources available for both sides and calculate the revised target as follows, always rounding down to a whole number.

- If the resources available to Team 2 (denote this by R2) are less than those for Team 1 (R1), then the target is revised downwards in proportion to the resources.

Thus Team 2's revised target = Team 1's actual score x R2/R1, plus one run. (One run less than the target gives a tie.)

If the resources available to Team 2 are greater than those for Team 1, then Team 2's target must be revised upwards. The excess runs required are calculated by applying the excess resource to the average 50-over total of 235 (or whatever number is decided upon for the appropriate class of game).

Thus Team 2's revised target = Team 1's actual score + (R2 - R1) x 235/100, plus one run. (One run less than the target gives a tie.)

[sallu123]

[a1kashur]

this is rocket science...

[Ahmed]

Come on guys, i know it takes some time to figure out but it can't be that hard that no one can reply about its advantages or disadvantages and/or compare it with other possible methods.

[Sharaabi]

its plain stupid....

why do u need to do so much maghazmaari....when you have a simple method at hand. All you need to know is simple algebra to find the number of runs needed, once you have the remaining number of overs.

[andha_qanoon]

Originally posted by Sharaabi:
its plain stupid....

why do u need to do so much maghazmaari....when you have a simple method at hand. All you need to know is simple algebra to find the number of runs needed, once you have the remaining number of overs.

So you think if a team scored 250 in 50 overs and if rain interrupts the play and other team is able to bat 25 overs then 2nd team should make 125 to win.
Do you think its fair???

[Ahmed]

a_q, that's why opened this thread, to discuss such things. So can u tell us why that is NOT fair? i.e. to simply calculate averages?

[funguy]

Ahmed, either you have never played cricket or started following it recently.

It is very easy to score 125 in 25 overs with all wickets in hand than score 250 in 50. Average alone doesn't quantify the amount of work required. DL method takes all factors into account. Resources available (overs, wickets, etc ) are all taken into account while calculating a target.

I hope you can understand but the way you asked the last question, I don't think I will be making any sense to you.

[junoonie]

they simply use this formula

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

where Z(u, w) is the expected number of runs to be scored in u overs when w wickets have been lost. Z0(w) is the average total score if an unlimited number of overs were available and when w wickets have been lost. b(w) is a decay constant that varies with w, the number of wickets lost!!!!



isnt it so simple!

[Asif_k]

I dont think scoring 125 in 25 overs is as easy as it looks. I agree now a days lot of teams score 125-140 in first 25 overs, but that is mainly because they have the Field Restriction advantage in first 15 overs. Take out the field restriction advantage in first 15 overs and teams will cry to make even 100 runs in first 25 overs. Due to the field restrictions Openers take lot of chance and play shots they wont even dream of playing if there are enough fielders outside the circle.

I dont think D/L is a very good method.

[andha_qanoon]

Originally posted by Asif_k:
I dont think scoring 125 in 25 overs is as easy as it looks. I agree now a days lot of teams score 125-140 in first 25 overs, but that is mainly because they have the Field Restriction advantage in first 15 overs. Take out the field restriction advantage in first 15 overs and teams will cry to make even 100 runs in first 25 overs. Due to the field restrictions Openers take lot of chance and play shots they wont even dream of playing if there are enough fielders outside the circle.

I dont think D/L is a very good method.

It may not be the best..but there arent any beter than this....

suggest a better method?

[andha_qanoon]

Originally posted by junoonie:
they simply use this formula

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

where Z(u, w) is the expected number of runs to be scored in u overs when w wickets have been lost. Z0(w) is the average total score if an unlimited number of overs were available and when w wickets have been lost. b(w) is a decay constant that varies with w, the number of wickets lost!!!!



isnt it so simple!

Junoonie,
Actually D/L method works pretty much similar to this. And it might look simple to you and many of us who studied maths ,but may not be very simple to others.

Now after looking at your equation..issues come how to determine decay constant b(w) .In case of D/L method these constant are determined by using historical data.

[a1kashur]

Peace.

As long as D/L thing doesn't mess up Pakistani matches, I don't really care.
peace.

[Asif_k]

Originally posted by andha_qanoon:

It may not be the best..but there arent any beter than this....

suggest a better method?

Well I dont have one right now, But I think I can work out a better formula If you promise me that it will be implemented

[Faisal]

As I said in the other thread, this over-reliance on mathematical formula has messed up the minds of ICC gurus. They have complicated the whole thing.

Like today, Holland were asked to score 28 more runs than Australia to win. Its one thing that Holland never actually had a chance, but had it been two equal teams this would have sucked.

So, one thing is certain it can NEVER be fair.

D/L is bad because its so complex, but whatever crappy formula they used in 1992 was infinitely worse. Though the way D/L works its getting close to that distinction too.

So, instead of losing so many mental calories trying to work out such complex formula, they should just stick with the method en vogue in the 1980's.. simple average multiplied by the number of overs. The team batting second will score those runs, and the team batting first can blame the weather. End of story! Abhi bhi yehi hota hai.