Duckworth Lewis discussion thread

[GingerFurball]

Don't want to de-rail the match thread any further, so new thread for a new discussion.

I don't know if I've got the maths spot on for this, but a glance at Statsguru shows that the average RR in T20Is is 7.52, with the average RR for ODIs played since Jan 1 2005 being 5.01.

Based on England's RR of 9.55 yesterday, which is 129% of the average, an equivelant ODI score would have been 318, which according to duckworth-lewis.com would have seen the West Indies set 171 to win from 20 overs, which immediately seems like a much fairer total - in this hypothetical scenario, West Indies would need to score at 8.5 an over in response to a total of 6.36 an over, as opposed to 10 plays 9.55.

I think D/L is a good system, however the last 2 WC games between England and West Indies have shown its flaws when applied to Twenty20 cricket. IMO, the maths involved definitely needs an overhaul.

[Athlai]

NZ have had some shockers in ODIs recently too.

[Sir Alex]

Am not sure about the logic behind extrapolation of a t20 total to One day total just based on their run rates.

In other words a equating a 192 total in T20s to a 318 total in one days doesn't look too acceptable for me. I'd back competitive teams to chase down the latter more easily than the former.

[AaronK]

The rain is killing the tournment for me..

[King Pietersen]

Suppose that's what you get for organising games in Guyana over the rainy season.

[GingerFurball]

Originally Posted by Sir Alex

Am not sure about the logic behind extrapolation of a t20 total to One day total just based on their run rates.

In other words a equating a 192 total in T20s to a 318 total in one days doesn't look too acceptable for me. I'd back competitive teams to chase down the former more easily than the latter.

The maths behind it:

Average RR in T20Is: 7.52
England's RR: 9.55 = 1.29 times the average.

Average RR in ODIs over last 5 years: 5.01
5.01 x 1.29 = 6.36 = 318 runs in 50 overs.

The maths isn't perfect, but the D/L par score for an ODI which is reduced to 20 overs for the team chasing 318, with all wickets intact, is 170. That immediately seems a lot fairer than a par score of 59 from 6 overs for a team chasing 192.

It's an imperfect example, and the maths might be questionable, as I'm not a mathematician, but the T20 system does look like it needs a review.

edit: Teams batting 1st who set over 170 have won 88% of the time in T20Is.

[AaronK]

they could just freaking end the match rather than having players come in the field for 4 runs.. so freaking stupied.. having a tournment of this calibar in a place like West Indies was a wrong idea at the first.. now it is just freaking hard to wait till the rain is over..

[Sir Alex]

Originally Posted by GingerFurball

The maths behind it:

Average RR in T20Is: 7.52
England's RR: 9.55 = 1.29 times the average.

Average RR in ODIs over last 5 years: 5.01
5.01 x 1.29 = 6.36 = 318 runs in 50 overs.

The maths isn't perfect, but the D/L par score for an ODI which is reduced to 20 overs for the team chasing 318, with all wickets intact, is 170. That immediately seems a lot fairer than a par score of 59 from 6 overs for a team chasing 192.

It's an imperfect example, and the maths might be questionable, as I'm not a mathematician, but the T20 system does look like it needs a review.

edit: Teams batting 1st who set over 170 have won 88% of the time in T20Is.

Of course am not questioning your math mate, but the reasoning behind using run rates in T20s comparable to those in One days.

In the above example you extrapolated a total of 192 to 318 in a one day which then using DL you reduced back to 170 from 20 overs. ;wacko: So either the logic behind DL reducing a total of 318 to 170 in 20 overs is not fair, or your extrapolation of 192 to 318 is not. Because 192 cannot be equal to 170.

Methinks you're doing apples to oranges stuff here.

But I do agree with your premise that DL seriously need revision in T20s or be replaced by some other rule like super over.

[GingerFurball]

Originally Posted by Sir Alex

Of course am not questioning your math mate, but the reasoning behind using run rates in T20s comparable to those in One days.

In the above example you extrapolated a total of 192 to 318 in a one day which then using DL you reduced back to 170 from 20 overs. ;wacko: So either the logic behind DL reducing a total of 318 to 170 in 20 overs is not fair, or your extrapolation of 192 to 318 is not. Because 192 cannot be equal to 170.

Methinks you're doing apples to oranges stuff here.

But I do agree with your premise that DL seriously need revision in T20s or be replaced by some other rule like super over.

I'm not saying 192 is equivelant to 170.

My suspicion was that the D/L equation would have been much fairer to England had it been an ODI; I think the numbers I've come up with support that suspicion.

The equivelant score in an ODI, based simply on how much better England's performance was than the average, would be 318. A score of 318 would have required the Windies to chase 171 in 20 overs had it been a rain affected ODI; that appears to me to be a much fairer target than what transpired last night.

[Prince EWS]

Have never really agreed with any criticisms of it, TBH, including during the last game. The target was so small because of the runs WI hammered off the overs before the break. For over a third of the entire innings the were going at (IIRC) about 13rpo despite only needing 9rpo (at the time) and they didn't lose any wickets. That's all taken into account - what the West Indies thought they needed at the time they were batting in those first two overs. When that happens, of course the rest of the innings is going to be easy-going.

If anything, I think it's just shown that 6 overs just isn't a game of cricket, particularly when it's divided into two different parts chasing different totals. The D/L calculation was fine - people are blaming it, essentially, for putting such a big emphasis on 2.2 overs, but that's what happens if you play a six over contest. Cricket in any sense isn't supposed to be defined so wholly by such small sample sizes. If they can't make it to 15 overs they should just call it off IMO.

[Prince EWS]

Just to show how much those two overs before the break - quite justly, given the ridiculously short length of the game - actually changed things, the West Indies would've needed 73 to win off their 6 overs rather than the 60 they ended up chasing if the rain delay happened in the innings break and they never actually batted those 2.2 overs.

[nightprowler10]

Originally Posted by Prince EWS

If anything, I think it's just shown that 6 overs just isn't a game of cricket, particularly when it's divided into two different parts chasing different totals. The D/L calculation was fine - people are blaming it, essentially, for putting such a big emphasis on 2.2 overs, but that's what happens if you play a six over contest. Cricket in any sense isn't supposed to be defined so wholly by such small sample sizes.

This, totally. No way should the game go on if you can only play 6 overs. Even in my 30/30 league I have to call a match officially rained out if 20 overs can't be bowled. For T20 I reckon it should something like 13 overs.

[GIMH]

The last two posts make a lot of sense. I guess any kind of reduced target is going to seem easier when the overs are lower - wickets become meaingless really.

However, I may revise my opinion. As things stand we are walloping these Thierry Henry haters quite comfortably according to DL. One over constitutes a game IMO.

[Sir Alex]

Originally Posted by Prince EWS

Just to show how much those two overs before the break - quite justly, given the ridiculously short length of the game - actually changed things, the West Indies would've needed 73 to win off their 6 overs rather than the 60 they ended up chasing if the rain delay happened in the innings break and they never actually batted those 2.2 overs.

Wow, how did you arrive at that? I mean the calculation for that?

I think it wouldn't have made any difference whether they'd been 30 or 0 at the break as long as they had not lost any wickets. Because DL takes into account the 'resources available' at time of break and resumption which is a product of wickets lost and overs remaining.

[Prince EWS]

I played around with the online calculator. Could've stuffed it up though.

But yeah, it does take into account the resources available, but it also takes into account how many runs are actually left to win. It's assumed that they'd have scored more quickly if they knew the innings was shorter, so the later the break is, the smaller the target becomes.

As I said in the other thread - imagine chasing 250 in an ODI, going off after 19 overs at 0/100 and then coming back on and being told that you needed to score 46 to win off one over because that's the 20 over equivalent of a 50-over 250. What you've already scored is taken into account.