Below is the exchange of e-mails between Mike Griffiths and the EBU on this topic. In view of the EBU's reply we will continue using duplimated boards as now. In the light of their view on rule 6E4, we will review whether or not to discard sets where the distribution of points is outside the range 49% - 51%. [The decision was to cease monitoring the range of high card points to NS and EW, on the advice of the EBU.]
From: John Pain <John@ebu.co.uk>
To: Mike Griffiths
Sent: Tue, 21 September, 2010 10:10:41
Subject: RE: Duplimated boards
We donít have a statement on duplimated boards Iím afraid. They are now accepted at EBU events without question and going back would be unheard of! I think the biggest pro is that we use them for almost everything we run.
Funny Ė they donít remember the times when they played hand dealt boards which were all one way. And Iíve seen some very skewed distributions of HCPs with duplimates as well. We played a set last night where N have an average of over 11 with the others all just over 9. I also played a set where my average was barely over 7. I was really fed up. Iíve certainly played in a howell and followed dreadful cards whether duplimated or not.
Our little club has been using duplimated boards from the start and wouldnít have it any other way.
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From: Mike Griffiths
Sent: 20 September 2010 18:42
To: John Pain
Subject: Duplimated boards
A minority of our players complain about having to play duplimated boards. The usual objections are (1) the distributions are too unpredictable and (2) you can play an evening and get a very poor share of the 'good cards'. We have repeatedly answered with logic, but the old 'intuitive' feelings keep coming back!
Is there, or could there be (please) an official EBU statement on the pros and cons of duplicated boards, to which we could refer these members?
I had an interesting exchange with one of my fellow members.....
Advantages of duplicated boards (apart from the trivial one of avoiding dealing at the table):
1. Duplimating produces truly random hands.
2. Theoretical percentage tables (suit divisions etc) can confidently be applied.
3. Provided the duplimate operator applies our recommended criteria (operators are asked to reject any set which distributes the high card points outside of the range 49% - 51%), NS and EW total high card points can be made approximately equal.
4. A copy of the hands can be provided, plus (in most cases) publicised on the website - an aid to partnership discussions.
Truly random hands are more unpredictable, therefore more difficult to bid and play than hands manually dealt after an inadequate shuffle, which tend to be more balanced with more even suit breaks. This takes players out of their "comfort zone".
Some players appear to believe that duplicated boards are the cause of certain players suffering a poor share of the high cards during the course of a session. This is not so. If they are prepared according to our criteria, and if a Mitchell movement is played, leaving as few as possible of the hands 'fallow', the duplication process can actually prevent this from happening. Manually dealt hands, however, are subject to no controls and may be significantly biased for or against NS.
Howell movements (and, to a lesser extent, hesitation Mitchells) are always likely to give some pairs a poor share of the points. Over the course of a year, statistically, most players' experience will even out. This is just one of the "chance" aspects of the game that has to be accepted, like receiving "gifts" from opponents and suffering when they underbid and get a top. If these unpredictables were not present, how often would you enjoy the satisfaction of our best players performing worse than you?
1 For some players ( inc me ) , the truly random nature of dup boards is an advantage , not a disadv - in the non-dup sessions you often play or defend 1nt all session, and I think this is worth hammering home ,though you do allude to it . Also , I suspect ( not sure if there is any scientific backing for this, prob just my prejudice. It could easily happen at rubber bridge, where cards are played on top of each other. At duplicate, it may also happen as a consequence of a player leading out a solid suit from the top - the effect will be reduced if players shuffle their cards before returning them to the board.) that you find eg AQ sat over KJ more often than you'd expect , due to bad shuffling
2 The issue of having eg 5x5 rounds rather than a Howell maybe needs spelling out more,as this is lobbied to me at least once a month . I know Colin has a strong opinion on this ,which I tend to support - you can find yourself playing a biased sample of the players in the room eg all the good ones, which would give people another cause for complaint!
3 In your section where you say there is a view (it's a fact, because almost every pair plays a different combination of NS and EW hands) that Howells can give an unfair share of points , I think this view is only expressed when one is e/w then switches at various points to n/s , when people say " we had all n/s 's bad hands , then we switched and had all e/w's bad hands" . Is there a killer argument we can use sorry, no to say that this is not true? The view is expressed after Howells too, but in general people are more inclined to accept it as the luck of the draw. (However, I think this is one of the reasons that generates the pressure for a 5x5 Mitchell.) 'Luck of the draw' is exactly what it is for Hesitation Mitchells too - but there is more chance of people feeling they have been 'singled out' to receive the worst of the cards. However, I think (over time, at any rate) poor card holding an illusion. It's not helped by the statistical fact that you are dealt more hands of less than 10 points than hands of more than 10 points.
Please just say if my request isn't viable.
Tunbridge Wells BC