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The EBU defines "duplicate bridge" The 75% Rule

#41 User is offline   Vampyr 

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Posted 2015-August-03, 13:12

 StevenG, on 2015-August-03, 01:05, said:

The EBU live in a parallel universe. Players don't discuss the hands after the game; they hobble slowly to their cars and pray that they are stll awake enough to drive home safely.u


In London it is pretty common to discuss hands either at a pub or at the venue, if they have a bar.

 Jeremy69A, on 2015-August-03, 06:51, said:

Although that is extreme there is certainly a club where 22 tables has been found using one section.


A club that expects 22 tables canes silly prepare another set of boards. Smaller clubs will have more serious problems.

Quote

If you take the more common example of 11 tables then playing 24 boards you have quite a lot of boards not in common. If you discuss them afterwards which I accept many will not do then that is at least partially spoilt but playing only some boards in common has been compared to having a round of golf where competitors play about 13 of the 18 holes and they are different to another competitor. Would you award ranking points for that? I wouldn't.


Playing 24 out of 33 boards is not ideal, but do not forget that nine will be the maximum boards you will not have in common with another pair. With all other pairs the number will be smaller,

 RMB1, on 2015-August-03, 12:50, said:

The Bowman (= Web) movement does not involve a revenge round.
EW move up one table each round and play 8 of the 11 NS pairs.

It is best with two sets of boards, otherwise 10 shares with 1 and 11 shares with 9,7,5,3,1,8,6,4


Yes, I was wondering whether the problem with one of the suggested movements was a two-board share. This is not an option for many clubs. Same goes for two sets of boards.

Quote

Playing only 8 rounds (24 boards) it is possible to omit round 5 rather than round 9.
After 4 rounds, EW up 2, boards down 2. This avoids the triple share between tables 1,10,11.


Loving the 2-board triple share, though.
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#42 User is offline   Trinidad 

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Posted 2015-August-03, 14:19

 Vampyr, on 2015-August-03, 13:12, said:

Yes, I was wondering whether the problem with one of the suggested movements was a two-board share. This is not an option for many clubs. Same goes for two sets of boards.


Loving the 2-board triple share, though.

You were talking about 8x3 boards. There shouldn't be a problem sharing 3 boards between 2 tables.

Rik
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#43 User is offline   Vampyr 

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Posted 2015-August-03, 16:30

 Trinidad, on 2015-August-03, 14:19, said:

You were talking about 8x3 boards.


Well, no, but whatever.
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#44 User is offline   RMB1 

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Posted 2015-August-03, 17:20

 Vampyr, on 2015-August-03, 16:30, said:

Well, no, but whatever.

You asked whether both 11-table two-winner movements had a revenge round.
I answered that one didn't and that was an 8-round movement.
Someone said that involved 2-board rounds and therefore impractical sharing.
Trinidad said it was 3-board rounds.
So yes, we were talking about "8x3 boards"
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#45 User is offline   Vampyr 

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Posted 2015-August-03, 17:26

 RMB1, on 2015-August-03, 17:20, said:

You asked whether both 11-table two-winner movements had a revenge round.
I answered that one didn't and that was an 8-round movement.
Someone said that involved 2-board rounds and therefore impractical sharing.
Trinidad said it was 3-board rounds.
So yes, we were talking about "8x3 boards"


Ah right, my mistake. Well, this movement might work then if the sharing is not a problem.
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#46 User is offline   Trinidad 

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Posted 2015-August-04, 00:17

Well, if you have 11 tables and less than 11 board sets, you don't need a PhD in math to figure out that you need to share boards.

Rik
I want my opponents to leave my table with a smile on their face and without matchpoints on their score card - in that order.
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#47 User is offline   Vampyr 

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Posted 2015-August-04, 05:26

 Trinidad, on 2015-August-04, 00:17, said:

Well, if you have 11 tables and less than 11 board sets, you don't need a PhD in math to figure out that you need to share boards.

Rik


No, but it might be difficult at some clubs.
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#48 User is offline   Gerben42 

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Posted 2015-August-04, 15:21

Sorry but I am with the EBU here. Why would anyone choose a movement where you play less than 75% of the boards other than laziness? In our club we everyone plays all boards except for two cases:

if we have an odd number of pairs (obviously) and if we have an even number of pairs but the number of rounds is one more than the number of tables (e.g. 11 rounds and 10 tables. in this case we play the movement for 12 rounds 10 tables and omit the last round.

For 11 tables 8 rounds we would play two groups with sharing (no problem with 3-board rounds).

If you play 11 tables 24 board btw why not play 12 two-board rounds from the 11 tables 13 round movement? (Requires boards 1-26)
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#49 User is offline   Vampyr 

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Posted 2015-August-04, 16:41

 Gerben42, on 2015-August-04, 15:21, said:

Sorry but I am with the EBU here. Why would anyone choose a movement where you play less than 75% of the boards other than laziness?


I can think of reasons other than laziness. Maybe the very inexpert volunteer director doesn't know how to run a different movement or how to enter it into his computer or program it into his Bridgemates (if he has them). Maybe the club have "always done things this way" and the members are very resistant to change.

I think that it must be he case that people like masterpoints; otherwise the EBU would not bother to issue them and would not be threatening to take them away. And I think that there are clubs, primarily provincial and social-oriented, which will unaffiliate rather than continue to pay the EBU and not receive masterpoints. Or at least will not pay for the games In which the movement does not suit. And this affects me.

At the end of the day I just wonder why the EBU is getting all hot and bothered about the tiny quantities of masterpoints given out in club games. I would prefer they concentrate on improving the increased services, reduction of paid staff and increased revenue that P2P has produced (at least I assume it has; that is what we were promised anyway).
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#50 User is offline   Trinidad 

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Posted 2015-August-04, 17:32

The point of duplicate bridge is that the same boards are played over and over again (hence the name "duplicate"), to get a decent amount of results on the noard.

To me it seems fairly obvious that one of the criteria for a good duplicate game should be to have a board played as many times as possible. There are other criteria too, so sometimes a board is not played the maximum possible number of times, but somewhat less. But it is entirely reasonable to set a minimum and 75% of the possible maximum seems like a minimum requirement to me.

So what would you do if you would have 27 tables? Put out 27 board sets on the tables and play 8 rounds of Mitchell?

Rik
I want my opponents to leave my table with a smile on their face and without matchpoints on their score card - in that order.
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#51 User is offline   Vampyr 

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Posted 2015-August-04, 19:08

 Trinidad, on 2015-August-04, 17:32, said:

So what would you do if you would have 27 tables? Put out 27 board sets on the tables and play 8 rounds of Mitchell?


Yeah, similarly for 100 tables or 1000. Or 1000000. This is silly.

What would be interesting, though, is to learn what requirements other federations have. Many years ago the ACBL allowed play of 24 out of 36 boards. Presumably this is no longer permitted?
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#52 User is offline   Trinidad 

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Posted 2015-August-05, 00:11

 Vampyr, on 2015-August-04, 19:08, said:

 Trinidad, on 2015-August-04, 17:32, said:

So what would you do if you would have 27 tables? Put out 27 board sets on the tables and play 8 rounds of Mitchell?



Yeah, similarly for 100 tables or 1000. Or 1000000. This is silly.

It is not silly. It shows that there will be a point where you need to share boards or duplicate them to have a proper comparison within the field (or give up and play multiple fields). Once you realize that there is such a point, you need to decide where to put it. This is, of course, arbitrary. The EBU put it at "everybody plays 75% of the boards in play". That seems like a reasonable value to me.

Rik
I want my opponents to leave my table with a smile on their face and without matchpoints on their score card - in that order.
The most exciting phrase to hear in science, the one that heralds the new discoveries, is not “Eureka!” (I found it!), but “That’s funny…” – Isaac Asimov
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#53 User is offline   gordontd 

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Posted 2015-August-05, 02:09

 Vampyr, on 2015-August-04, 19:08, said:

Yeah, similarly for 100 tables or 1000. Or 1000000. This is silly.

And yet there is at least one club that chooses to play movements where the percentage of boards played/boards in play is 50% - ie every pair has as least one other pair with whom they have no boards in common. Not very "duplicate".

I must say I'm surprised at your response to this whole question Stefanie: since you go on at every opportunity about the unfairness of single-winner IMP pairs games, I rather expected you to be on the other side of this one and like the idea of encouraging fairer movements.
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#54 User is offline   Vampyr 

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Posted 2015-August-05, 07:52

 gordontd, on 2015-August-05, 02:09, said:

And yet there is at least one club that chooses to play movements where the percentage of boards played/boards in play is 50% - ie every pair has as least one other pair with whom they have no boards in common. Not very "duplicate".


I agree that this is absurd, but...

Quote

I must say I'm surprised at your response to this whole question Stefanie: since you go on at every opportunity about the unfairness of single-winner IMP pairs games, I rather expected you to be on the other side of this one and like the idea of encouraging fairer movements.


A fair movement is very important to me personally, but I read a letter in Mr Bridge in which a person complained bitterly about the new policy. This got me thinking that there are probably quite a few clubs somewhere in the back of beyond where the concept of a fair movement is unknown and if it were known people wouldn't care. I think that the EBU need to recognise that not every place is London or similar, and that a one-size-fits-all approach may not, actually, fit all. Not all bridge players are keen competitors; in fact these are probably outnumbered by those who just want to spend a social afternoon or evening enjoying themselves. If these people are happy, I think that a better policy would be simply to let them be. They are not hurting anyone.

Now if a member of one of these clubs has complained, which I think is pretty likely considering that the issue has come up, then there is a bit more of a problem and maybe this policy, however heavy-handed it may seem, is the best solution, but perhaps it could be kept a bit quieter and not necessarily applied in places where no one has expressed dissatisfaction?

And now you mention it, should not a similar policy apply to one-winner IMP pair games? B-)
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#55 User is online   helene_t 

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Posted 2015-August-05, 08:09

Suppose you have two sections (players randomly assigned) and you for some reason decide to treat them as a single section although there was zero overlap between the boards played. Then the fraction of the boards which each pair played would drop form 100% to 50%. Would it make any difference to the interpretation of the results? Someone who was 3rd in his own section would now on average be shared 5th in the overall section. Of course if the two sections are not equally strong it does make a substantial difference.
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#56 User is offline   gordontd 

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Posted 2015-August-05, 08:21

 helene_t, on 2015-August-05, 08:09, said:

Suppose you have two sections (players randomly assigned) and you for some reason decide to treat them as a single section although there was zero overlap between the boards played. Then the fraction of the boards which each pair played would drop form 100% to 50%. Would it make any difference to the interpretation of the results? Someone who was 3rd in his own section would now on average be shared 5th in the overall section. Of course if the two sections are not equally strong it does make a substantial difference.

It would make a big difference to the master points.
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#57 User is online   helene_t 

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Posted 2015-August-05, 08:24

 gordontd, on 2015-August-05, 08:21, said:

It would make a big difference to the master points.

So you get more masterpoints for ending shared 5th of 48 than for ending 3rd of 24? Or fewer?
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#58 User is offline   gordontd 

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Posted 2015-August-05, 08:29

 helene_t, on 2015-August-05, 08:24, said:

So you get more masterpoints for ending shared 5th of 48 than for ending 3rd of 24? Or fewer?

You would get twice as many for coming 5th out of 48 than for coming 3rd out of 24.
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#59 User is offline   WellSpyder 

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Posted 2015-August-05, 09:36

 gordontd, on 2015-August-05, 08:29, said:

You would get twice as many for coming 5th out of 48 than for coming 3rd out of 24.

Where were you when I was having this discussion about master points in 1 vs 2-winner movements?
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#60 User is offline   gordontd 

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Posted 2015-August-05, 09:45

 WellSpyder, on 2015-August-05, 09:36, said:

Where were you when I was having this discussion about master points in 1 vs 2-winner movements?

I saw it, but since campboy was replying I didn't need to add anything. But it's a different question than the one being addressed here.
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