[zasanya]

I was told that in a scrambled Mitchell movement 25% of the total deals should be 'arrowswitched'. Is that true? If yes, please explain why.

[Vampyr]

 zasanya, on 2017-February-13, 19:27, said:

I was told that in a scrambled Mitchell movement 25% of the total deals should be 'arrowswitched'. Is that true? If yes, please explain why.

25% is incorrect 12.5% is right.

I cannot give you the numbers, but this optimises comparisons with players in the opposite direction.

[fromageGB]

Would it be a better comparison if boards were switched for part-rounds?
For example, in an 8 table 3-boards-a-round, rather than switch the last round, you switched the first board on round 6, the second board on round 7, and the last board on round 8?

[Vampyr]

 fromageGB, on 2017-February-14, 05:52, said:

Would it be a better comparison if boards were switched for part-rounds?
For example, in an 8 table 3-boards-a-round, rather than switch the last round, you switched the first board on round 6, the second board on round 7, and the last board on round 8?

And then you could go to the computer and enter in all the tables that failed to arrow-switch...

I have always thought there should be arrow-switches in Swiss Pairs, but the same problem would apply.

[gordontd]

 Vampyr, on 2017-February-14, 05:55, said:

And then you could go to the computer and enter in all the tables that failed to arrow-switch...

I have always thought there should be arrow-switches in Swiss Pairs, but the same problem would apply.

Yes, an arrow-switching schedule could be improved if done on a board-by-board basis, but it would be likely to cause lots of failures to comply.

[blackshoe]

I don't know if "cause" is the right term. Certainly it would lead to that, but the cause would, I think, be failure to educate players and also failure of players, "educated" or not, to understand or remember that they should comply.

[barmar]

 blackshoe, on 2017-February-14, 10:32, said:

I don't know if "cause" is the right term. Certainly it would lead to that, but the cause would, I think, be failure to educate players and also failure of players, "educated" or not, to understand or remember that they should comply.

You're distinguishing ultimate and proximate cause, but does it really matter? The result will still be the same: confusion. If you try to run a complicted movement, you have to be prepared to deal with the inevitable mistakes.

[chrism]

One reference explaining the 1/8 guide is this article by Ross Moore

[blackshoe]

 barmar, on 2017-February-15, 10:10, said:

You're distinguishing ultimate and proximate cause, but does it really matter? The result will still be the same: confusion. If you try to run a complicted movement, you have to be prepared to deal with the inevitable mistakes.

Yes, you do.

[Vampyr]

 blackshoe, on 2017-February-14, 10:32, said:

I don't know if "cause" is the right term. Certainly it would lead to that, but the cause would, I think, be failure to educate players and also failure of players, "educated" or not, to understand or remember that they should comply.

Here sometimes players to fail to arrow-switch the first board of a round. It is not often, but it happens. Is your experiene different? Also, at least at present, Bridgemates can display compass positions in a round, but not for a single board.

On a related note, at the famous North London bridge club, we have to play revenge rounds with 12 tables, because the chief tournament director does not trust the players to handle a double-weave Mitchell. Player education cannot accomplish miracles.

[gordontd]

 Vampyr, on 2017-February-15, 18:06, said:

On a related note, at the famous North London Bridge club, we have to play revenge rounds with 12 tables, because the chief tournament director does not trust the players to handle a double-weave Mitchell. Player education cannot accomplish miracles.

The CTD doesn't trust them to player a share-and-relay Mitchell either?

[Vampyr]

 gordontd, on 2017-February-16, 01:20, said:

The CTD doesn't trust them to player a share-and-relay Mitchell either?

(Translation for Americans: relay-and-byestand)

The trouble is that the session cannot run over three hours, so the club cannot handle any delays associated with sharing two-board rounds.

[barmar]

 Vampyr, on 2017-February-15, 18:06, said:

On a related note, at the famous North London bridge club, we have to play revenge rounds with 12 tables

Am I the only one who was thinking that at this club, "revenge" is likely to have a different meaning?

[mycroft]

I can imagine that, in order to get one particular spot to be filled, they may have to award a free entry, at least...

[Edit: I'm sure this was obvious, but Just In Case, I'm not referring to Vampyr here...]

[blackshoe]

 Vampyr, on 2017-February-16, 04:19, said:

(Translation for Americans: relay-and-byestand)

The trouble is that the session cannot run over three hours, so the club cannot handle any delays associated with sharing two-board rounds.

I must have missed something. Where is there sharing in a double-weave Mitchell?

[gordontd]

 blackshoe, on 2017-February-16, 23:08, said:

I must have missed something. Where is there sharing in a double-weave Mitchell?

You have missed something. I wondered why, if they couldn't do a double weave, they couldn't do a share-and-relay rather than having a revenge round.

[blackshoe]

 gordontd, on 2017-February-17, 01:47, said:

You have missed something. I wondered why, if they couldn't do a double weave, they couldn't do a share-and-relay rather than having a revenge round.

Fair enough.

[BudH]

Too bad I won't be able to use any of this Scrambled Mitchell information at my local club. Earlier this month, my local club Board of Directors relieved me of my Head Director duties and then shortly thereafter instructed me not to use any arrow switched (scrambled) Mitchells (because so many players have complained about them - funny that in 6-table Howells when the table card is rotated at Tables 2 and 3 and opponents bid a slam they think nothing of it - but if I arrow switch the final round at ALL tables and the same thing happens, I have ripped the enjoyment of bidding and making 7NT from their hearts!)

The ratio of switched rounds to total rounds is optimized (depending on which sources you look at) when it equals

0.25 - (T-1)/(8T-4), where T = number of tables

Note for 5 to 16 tables, the ratios below are all slightly more than 1/8 (12.5%) confirming the common 1/8 guideline.

5, 13.89%
6, 13.64%
7, 13.46%
8, 13.33%
9, 13.24%
10, 13.16%
11, 13.10%
12, 13.04%
13, 13.00%
14, 12.96%
15, 12.93%
16, 12.90%

[mycroft]

Heh, re: Revenge Round:

Last week I was in Bangalore. I played in one of the club games there.

20 tables. 20, one-board rounds, with a skip and a revenge round.

First time I've seen *that* movement.

The TD asked me (who knew I was a part time ACBL TD) what I do about perenially slow players. I mentioned that since we usually play two- or three-board rounds, at least I had *one* board to move...

[weejonnie]

 mycroft, on 2017-April-04, 15:44, said:

Heh, re: Revenge Round:

Last week I was in Bangalore. I played in one of the club games there.

20 tables. 20, one-board rounds, with a skip and a revenge round.

First time I've seen *that* movement.

The TD asked me (who knew I was a part time ACBL TD) what I do about perenially slow players. I mentioned that since we usually play two- or three-board rounds, at least I had *one* board to move...

Wonder whether the TD knows the word 'duplicate' has more than one meaning in bridge. I suppose if your'e playing 20 1 board rounds then you could play a 20 table 24 board web Mitchell just as quickly. But maybe the club only has one set of boards . . . If the hands have to be dealt then it will only take a few minutes for them to be duplicated and the copy passed over to the other table.