[ffb3503071]

I would like to know before the beginning of the tournament, where will each player sit at the first position, is there a rule used by BBO ?

I have noticed that the player who invites his/her partner will sit in West or South, but I have not found anything else yet

TY
JHF

[barmar]

Yes, the inviter is always South or West.

I don't think much else is predictable.

[Jim9baker]

Can the director set up tables based on ACBL classification of ABC levels so that teams start at each table have a similar demonstrated ability level?

[barmar]

Jim9baker, on 2020-May-31, 21:03, said:

Can the director set up tables based on ACBL classification of ABC levels so that teams start at each table have a similar demonstrated ability level?

No. What would be the point of that? They'll get different opponents in subsequent rounds.

The system automatically distributes the ABC players to even out the field.

[Jim9baker]

In normal ACBL bridge club tournament, to even things out the first round table 1, an A level team plays an A level team, table 2 is a B level tesm plays a B level team and the 3rd table a C level team plays a C level team and an attempt is made to continue this sequence. The purpose is to even the field so each team level plays an equal level of a ABC level teams. This avoids the semi random setup I see presently where C level teams sometimes play a disproportionate number of A level teams and A level teams get to beat up on a disproportionate number of C level teams. I have seen a couple of events were a B level team played 4 A level teams and got beat by an A level team by 2 points in raw score that had play 3 C level teams, a really good day for the B team but not really a level playing field. Leveling the playing field at the beginning of play would at least guarantee playing against the same number of ABC teams or close to it.

[Jim9baker]

I am looking at the virtual club matches specifically.

[mycroft]

We (ACBL Club and Tournament directors) do this, yes, but then again, we don't.

The intent is to ensure that:

• there are the same number of A's, B's, and C's;
  
• there's no clump of strong or weak players, meaning that if there's some pairs that are missed, there's no "muderer's row" that a lucky pair could miss all of; and
  
• in fields where it matters, the A field is *also* stratified, and the two items above are done again for the experts, as opposed to just A players. The tables set for "seeded A's" are also set in such a way as to ensure as much as possible that no seed gets the benefit of missing more seeds than others.

Now it turns out that the easiest way to do that is to make A, B, and C tables (and seeded A vs regular A tables), so round 1, A's play A's, B's play B's, and so on. But that's just a side-effect. We could with a little more work (and I've done it with a little inattention; once I noticed, I just kept it up throughout the sale) sell an AX game, say, by having odd tables N-S A and even tables E-W A, so that round 1, all matches were A vs X. One of the tricks used in one-section, two-session games for running the crossover is "shift E-W N tables" where N is the difference between tables-in-play and rounds; that means that even if there are playbacks, at least for those N rounds, there will be new opponents. But of course, if N doesn't line up with the A/B/C map, then of course round 1 (of the second session) will not be A vs A.

Provided:

• the fields are spread out well when placed, so tables 7-11 aren't all the N-S A pairs;
  
• the fields are stratified well (with equal A/B/C N-S and E-W, potentially even using MPs to also ensure the 5K+ pairs are split evenly); and
  
• if the game is split into sections, the above apply to both sections;

It doesn't much matter if the C pairs play an A pair or a C pair first round. You'll play approximately 3 A's, 3 B's, and 3 C's in your 9 rounds for your 18 boards.

Now if only [Local TD/BBO] would set up their game so that my partner and I don't have to play [arguable top pair in city] *every* *single* *game*. I don't mind playing them, but can we get one game when someone else has to survive them to get their 60%? :-)

[Jim9baker]

So are you saying that BBO does this by default or does the TD have to set this up? I am I guess a little simplistic in that I know if you have a balanced set of ABC teams, then the first table A teams, 2nd Table B team, 3 rd table C team etc will work nicely. If not balanced you can not guarantee balanced resulting pairing. I am seeing unbalanced results with what I think are relatively balanced number of ABC teams

[mycroft]

I have no idea how BBO sets players. It may in fact be totally random. I would hope it was better than that.

I was just saying that the "first round play at your level" has nothing to do with balance, it's just a side-effect of the default pattern used to produce the balance.

[barmar]

Jim9baker, on 2020-June-03, 14:13, said:

So are you saying that BBO does this by default or does the TD have to set this up?

Seating is all done automatically. There's no way for the TD to seat players by hand or specify any seating rules.

[barmar]

mycroft, on 2020-June-04, 09:15, said:

I have no idea how BBO sets players. It may in fact be totally random. I would hope it was better than that.

I was just saying that the "first round play at your level" has nothing to do with balance, it's just a side-effect of the default pattern used to produce the balance.

It's just an easy way to try to roughly balance NS and EW in face-to-face games.