[tournament-org] McMahon Bar

[Geoff Kaniuk]

This is a really good example why it is very important to take into 
account the distribution of player strengths, and not rely on bar 
setting guidelines which are based purely on number of rounds.

There is a concept - the 'supergroup' - which was invented precisely to 
deal with this kind of situation. Admittedly this is more common in very 
long tournaments with many strong players - e.g. the European Go 
Congress, but as here it does have general application.

GoDraw has a feature to create supergroups. In this case the process 
results in setting a basic bar at shodan (MMS=0) but a supergroup 
consisting of 2d and 3d (MMS=2). In this case it is equivalent to just 
setting the bar at 2d because the bar group is homogeneous. For the 
first two rounds the supergroup play each other, but the shodans get 
their chance in round 3!

You can of course split the 1d on GoR as you say, and I can advise how 
to actually do it in GoDraw without much fuss. But I would like to 
emphasise that when doing this kind of thing, one should not rely on 
current GoR value alone. Rating can be very noisy for many players, and 
that includes top players by the way!

It is vital to look at the player rating history in EGD for each of the 
seven 1 dan players. It may be obvious from their graphs who is stable, 
or who is underrated or overrated, or you may see chaos. In the latter 
case I would strongly advise to take the average of the last 10 games - 
assuming that they were played within the last 3 years say. In fact to 
be fair, one should use an average for all the players under 
consideration.  It would also be worth looking at the 3d,2d history to 
be sure.

Hope this helps.

PS I wonder what has triggered your example?

Geoff

33 Ashbury Close, Cambridge CB1 3RW 01223 710582

On 29/07/2020 12:23, Matt Marsh via tournament-org wrote:
> Hi all,
> 
> I've been pondering this:
> 
> Let's suppose I am organising a tournament and I have a distribution of 
> players towards the top a bit like this:
> 
> 3d, 2d, 2d, 2d, 1d, 1d, 1d, 1d, 1d, 1d, 1d, 1k, 1k, ...
> 
> If it's a 3 round tournament then I'd ideally like 8 players above the 
> bar. If I took the 3-dans, 2-dans and 1-dans then I would have 11 players.
> 
> Would it be appropriate to split the group of 1-dans, based on GoR, so 
> that some of the 1-dans are above the bar and some are below it? ie. 
> some 1-dans would have a different inital MMS to the others.
> 
> Matt
> 
> -- 
> *Matt Marsh*
> matt at crazedbytes.net <mailto:matt at crazedbytes.net>
> +44 (0)7795 297779 <tel:+44-7795-297779>
> 
> 
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