[McBruce]

I don't understand the part that says that Butler compares to -18... how does the number of results come into it?

1 x 1460
4 x 1430
1 x 1400
1 x 800
2 x 710
7 x 680
2 x -100

1460 wins 11 once, total +11
1430 wins 11 four times, total +44
1400 wins 10 once, total +10
800 loses 3 once, total -3
710 loses 5 twice, total -10
680 loses 6 seven times, total -42
-100 loses 14 twice, total -28

11 + 44 + 10 - 3 - 10 - 42 - 28 = -18, so the average NS pair is -1! I think this is an extreme example, oddly enough I made it up out of thin air!

In Cross-IMPs the math works out so that it always balances.

When everyone plays 4S= and one pair plays 2S+2, every defending pair will get a bad result "for just sitting there".

Assuming 13 tables and vulnerable, in cross IMPs this is only a 0.83 IMP swing, since you lose ten once and push eleven times. Hardly a bad result. In Butler this would be an average because we discard the extremes: but who knows, maybe this is a board that only 12 out of 13 pairs will risk game on? Who are we to assume that it is a universal flat board because only 1 out of 13 pairs misses the game. My opinion is that a hand like this is an example of the disadvantages of Butler scoring.

If you Google 'Butler Cross-IMPs' you will find lots of online discussion on this.

[helene_t]

Removing the extremes only solves a small fraction of the problem. I don't think it's worthwhile.

Even with extremes removed, most of your succes (well, at least most of the succeses I enjoy in tournaments) will still come from opponents that make absurd bidding mistakes or other blunders.

It would be nice if the TD's had time to clean up dumping results, but still, dumping is not the major cause of outliers.

The only way to get clean results is to homogenize the field (when feasible), or to agregate over multiple sessions. Otherwize, don't take the results too serious. It's just a card game.

[coyot]

McBruce, on Jul 11 2005, 03:47 AM, said:

When everyone plays 4S= and one pair plays 2S+2, every defending pair will get a bad result "for just sitting there".

Assuming 13 tables and vulnerable, in cross IMPs this is only a 0.83 IMP swing, since you lose ten once and push eleven times. Hardly a bad result. In Butler this would be an average because we discard the extremes: but who knows, maybe this is a board that only 12 out of 13 pairs will risk game on? Who are we to assume that it is a universal flat board because only 1 out of 13 pairs misses the game. My opinion is that a hand like this is an example of the disadvantages of Butler scoring.

If you Google 'Butler Cross-IMPs' you will find lots of online discussion on this.

Oh, I see... you would have to use continuous IMP scale to get rid of this problem... that 910 Butler average happens to be near to the wrong (for NS) boundary on IMP scale...

To the quoted part:
If 12 of 13 pairs risked the game, I don't think they deserve any extra points... When the whole field bids it except for some natural pessimist, they don't play "better" bridge than the rest of the field. It is only the pessimist that should suffer on this board.

I think that we can safely assume that if a large majority of the field ends up in a game contract, the game contract should be considered "par of the board" and only those that score more than par should receive points.

If you look at it from the defending side: who are we to assume that the 12 NS pairs who bid the game play better bridge than the 12 EW pairs that just lost 0.83 IMP?

I think the scoring system should try it's best to reward those who play better bridge...

Who are we to assume that it is a universal flat board because only 1 out of 13 pairs misses the game.

Pardon me, but I thought that the definition of "flat board" IS a board where a large majority of pairs playing common bidding systems and not affected by opponents psycho bids end up in the same contract and score the same result.
Even if there are alternative ways of making the contract, if the large majority of pairs choses the one that succeeds, I consider it a flat board.

but who knows, maybe this is a board that only 12 out of 13 pairs will risk game on

It's about the same risk as betting that the next US president will be either a Democrat or a Republican... 12 of 13 people think so... and that is why no betting agency ever runs bets like this with win:bet ratio above 1 ).

In other words - cutting the extreme results would bring more good than bad - and it would bring the good largely to the pairs that were not able to affect the result significantly.

There is the question if and how could extreme-cutting be incorporated into cross-imps - how to determine the score for the pairs whose results were cut out as extreme (in order not to disrupt the IMP balance etc...)

IMHO Butler with fractional IMP scale would work quite well. We're using normalized IMPs with decimal parts already (although they have their nice whole IMPs behind them) and I think it would work quite well.
[But I promise to stop spamming the forums with this topic if noone else supports the idea :-)]

[Gerben42]

You can use Herman de Waels improvement of Butler instead:

For more information about "Bastille" see:

http://users.skynet....e/bastille.html

[reisig]

Why try to change a whole bridge scoring program because of a player that probably should be banned? The director should be called - and an adjusted score given. Then the crazy bidder be reported...and the proper punishment assigned by BBO.

[coyot]

reisig, on Jul 11 2005, 06:26 AM, said:

Why try to change a whole bridge scoring program because of a player that probably should be banned?  The director should be called - and an adjusted score given. Then the crazy bidder be reported...and the proper punishment assigned by BBO.

I mentioned above that there are two topics hidden in this:

1) How to keep the abuse at reasonable level (TD work, punishing bidders... is everyone going to call director when opponents give him 24 IMPs?)

2) Is the current scoring system fair?

While topic 1) has been settled (call TDs, report freak bidders to abuse@... and blacklist them if you're TD), topic 2) is quite interesting alone.

I personally find Butler with it's extreme cuts more fair in general than CrossIMPs. CrossIMPs are about the only feature of BBO that I dislike - because without the cuts, you're bound to get undeserved points (either way)...

Once I observed to a friend when explaining online bridge that for every 8-trick contract there will be one or two pairs playing game and for every game contract there will be one or two pairs playing a slam...

P.S. Working link to Bastille: http://users.skynet....a/calcul16.html

[McBruce]

coyot, on Jul 11 2005, 01:15 AM, said:

If 12 of 13 pairs risked the game, I don't think they deserve any extra points... When the whole field bids it except for some natural pessimist, they don't play "better" bridge than the rest of the field. It is only the pessimist that should suffer on this board.

I think that we can safely assume that if a large majority of the field ends up in a game contract, the game contract should be considered "par of the board" and only those that score more than par should receive points.

If you look at it from the defending side: who are we to assume that the 12 NS pairs who bid the game play better bridge than the 12 EW pairs that just lost 0.83 IMP?

I think the scoring system should try it's best to reward those who play better bridge...


Who are we to assume that it is a universal flat board because only 1 out of 13 pairs misses the game.

Pardon me, but I thought that the definition of "flat board" IS a board where a large majority of pairs playing common bidding systems and not affected by opponents psycho bids end up in the same contract and score the same result.
Even if there are alternative ways of making the contract, if the large majority of pairs choses the one that succeeds, I consider it a flat board.

In a 13-table matchpoint game with a top of 12, when one pair doesn't get to game, the pairs that do get 6.5 matchpoints, not an average of 6. Nobody has ever suggested that this is somehow wrong and the 170 should be discarded so that everyone can have average and the weird table should get some artificial score. A flat board is not one in which the majority of pairs achieve the same result, it is one in which ALL the pairs acheive the same result.

It's not always just incompetance that results in a 170 in a sea of 620s. Sometimes the opponents take a risk not taken at other tables; an agressive overcall, or maybe a psychic bid makes it not quite clear to even a good pair that the game should be bid. And what about the case when the contract only makes nine tricks and the minority pair are right not to bid on? You're going to rob them of their good board because "par" is -100! I don't see any justification at all for kicking out minority scores just because they seem a small nuisance to some.

Anyhow, the best solution to avoid these nuisances, if you take them as such, is to increase the number of times the board is played. I don't know what that number currently is in the Main Bridge Club, but there is no reason it couldn't be quite high, like say 50 or so. That way, the 620s will gain very little with only one 170 in the field.

[coyot]

McBruce, on Jul 11 2005, 04:59 PM, said:

Anyhow, the best solution to avoid these nuisances, if you take them as such, is to increase the number of times the board is played. I don't know what that number currently is in the Main Bridge Club, but there is no reason it couldn't be quite high, like say 50 or so. That way, the 620s will gain very little with only one 170 in the field.

This would be a great idea... Right now, the number is 16 (so that all results fit on the screen.

In fact, I don't really care about 170s in a field of 620... but sometimes you get 800 and 1100 in the field of 140s )

[pigpenz]

thats why i had posted earlier if people would be interesed in playing in a full 26 board event, its still a card game but bridge is a game of percentages, and the results are alittle skewed the less boards that are played.....plus people willing to committ the time to this would hopefully be a little more serious about the competition. i think

[luis]

In my opinion the only way to make individual trounaments civilized is to assign individual points to ALL the players in the tournament from 1st to last for example you can assign positive points to the players in the top half and negative points to the players in the bottom half depending on the # of players playing the winner gets more. You can then keep a stat for each player and for example play tournaments were some kind of requirement about such a stat should be met to play with 2nd tier tournaments open to all the players so they can play well and improve their rankings in order to qualify to the top-tier indys.
In this way all the hands count, even when you are having a bad tournament you won't like to do stupid things since it will be very different to be in the middle of the pack or last.

Just some ideas :-)

[pigpenz]

Luis:
you know I always thought the ACBL should do that, in all of their tourneys...Its like the Law of Total Entropy.
If you finish last in a tournament then you should lose whatever the winner wins, etc. Get a Section top win 3.00 Gold, section bottom Lose 3.00 Gold. No more I have 5000 masterpoints cause i have played for 50 yrs. You would want to be at 0:00 plus