[Phil]

More mps. Weak field.

KJx Ax KTxxx xxx

W/R

P 3S x 4S
5H p p ?

[JLOGIC]

el paso. I have enough defense to hope to beat them and obviously not enough to X.

[Lord Molyb]

What's the problem? We're not on lead.

[lalldonn]

Yes pass. Even if saving is right it will still lose to pairs that bought it in 4♠X, so going for a really good score by beating them has to be right, especially since it seems somewhat likely.

[JLOGIC]

lalldonn, on 2013-March-12, 18:22, said:

Yes pass. Even if saving is right it will still lose to pairs that bought it in 4♠X, so going for a really good score by beating them has to be right, especially since it seems somewhat likely.

in b4 someone says it must be right to save or X, ergo we should do one of those

[Phil]

You beat it one for slightly for slightly better than average. +200 is a top. My concern with passing (which I did) was that we have some equity to protect against some even weaker pairs that buy it for 3♠ or when you actually make 4♠.

Is -850 more likely than +200?

Gave the hand to someone I respect. He bid 5♠.

[neilkaz]

NOT 5♠..pass or X...I'd not criticize anyone who X'd vs a weak field as your likely getting quite a bad board in a weak field if they make 5♥. I play in too many weak fields and would lean towards X at MP in one. Would not X at IMPs as odds don't seem right. I'd never criticize a pd who passed at MP.

In a good field this is a MUCH tougher problem for me.

[JLOGIC]

Here is a simple illustration that shows that passing in the face of uncertainty can lead to the highest matchpoint EV even though it is never right to pass on any individual hand (if they were down Xing is right and if they aren't saving is right).

Imagine 5H makes half the time, and is down 1 the other half. Now imagine a hypothetical field of 6 other pairs. Their results are

2 people in 4S -1
2 people in 4H = or +1
1 pair in 5S X -2
1 person in 5H, either making or down 1

When 5H is making, double gets you a zero, pass gets you 1.5 matchpoints, and saving gets you 3.5 matchpoints.

When 5H is down 1, double gets you a top, pass gets you 5.5 matchpoints, and saving gets you 2.5 matchpoints.

So your EV from both Xing and saving is an average, and from passing is 3.5 matchpoints. That may not seem like a lot but consider the difference in a 50 % game and a 58 % game.

Notice I never had 4S making or down 2, but that does not effect the scores of any of our bids (5S would be down 3 and it still beats pass or double when 5H makes or loses when it's down).

Claytoen is right, the most important time to double is when there are people in partscore making your way and you beat them a trick. This seems silly to me though, what are the odds that they're cold for a game, and have bid to 5H r/w against us, but at other tables are not bidding 4H?

Far more likely if partners hand doesn't open 3S at other tables is that we are going to be on a freeroll if we pass, because many other tables play 4H. This means if 5H is down 1 we don't need to double to beat these people. However, if it makes 5 we give up a full half a matchpoint to these people by doubling.

In general when faced with this amount of uncertainty, the best course of action is going to not be to figure out what the field is in, but to figure out how likely you think you are to beat them. In cases where you feel like it's a reasonable shot but it could go either way, passing is usually best. If you feel strongly one way or another then either save or double.

[Phil]

JLOGIC, on 2013-March-13, 11:32, said:

Claytoen is right, the most important time to double is when there are people in partscore making your way and you beat them a trick. This seems silly to me though, what are the odds that they're cold for a game, and have bid to 5H r/w against us, but at other tables are not bidding 4H?

This was the actual matrix of the results.

RESULTS OF BOARD 15

SCORES MATCHPOINTS NAMES
N-S E-W N-S E-W
100 2.50 5.50 1-Lynch-Seltzer vs 6-Renkus-Harris
620 8.00 0.00 2-Linsenbard-Robbins vs 8-Brilliant-Weiss
50 5.50 2.50 3-Dale-Schennum vs 1-Miyauchi-Cowan Jr
100 2.50 5.50 4-Wicks-Dreier vs 3-Kendro-Zimmerman
100 2.50 5.50 5-Warren-Kristiansen vs 5-Krause-Skinner
300 7.00 1.00 6-Watkins-Watkins vs 7-Johnson-Dalladas
50 5.50 2.50 7-Sloan-Parks vs 9-Williams-Feigenbaum
100 2.50 5.50 8-Pride-Ellis vs 2-Clayton-Clements
140 0.00 8.00 9-Moskowitz-Witt vs 4-Katz-Johnston

At a few tables, some opened 2♠ w/r LOL with AQTxxxx x xx xxx. Most found a call over a spade preempt on x KJTxx AJ9x AKx (yes, our 5♥ bidder had xx Qxxxx Qx Qxxx!), so there was only one pair that bought the hand for 3♠. Doubling moves you from a 69% board to a 100% board, although if they were to make it, you go from a 37% board to a zero.

Looking at my hand, -1 looks a lot more likely than =. I'd be a lot more concerned about doubling if the auction was p 3♠ 4♥ 4♠; 5♥, and might even save in this sequence.

[Fluffy]

Phil, on 2013-March-14, 09:25, said:

This was the actual matrix of the results.

RESULTS OF BOARD 15

   SCORES      MATCHPOINTS   NAMES
  N-S   E-W    N-S    E-W
        100    2.50   5.50 1-Lynch-Seltzer vs 6-Renkus-Harris
  620          8.00   0.00 2-Linsenbard-Robbins vs 8-Brilliant-Weiss
   50          5.50   2.50 3-Dale-Schennum vs 1-Miyauchi-Cowan Jr
        100    2.50   5.50 4-Wicks-Dreier vs 3-Kendro-Zimmerman
        100    2.50   5.50 5-Warren-Kristiansen vs 5-Krause-Skinner
  300          7.00   1.00 6-Watkins-Watkins vs 7-Johnson-Dalladas
   50          5.50   2.50 7-Sloan-Parks vs 9-Williams-Feigenbaum
     -->100    2.50   5.50 8-Pride-Ellis vs 2-Clayton-Clements
        140    0.00   8.00 9-Moskowitz-Witt vs 4-Katz-Johnston

[JLOGIC]

Phil, on 2013-March-14, 09:25, said:

Looking at my hand, -1 looks a lot more likely than =.

Well then obviously you should X if you feel that way. That is my point, just because it is matchpoints, the main decision on doubling (or saving) is still just how often are you going to beat them. It does not have to be a huge in depth thing, if you think you are beating them a lot more than they're making then double. If you think they are big favorites to make then save.

But there is a happy medium with pass if you just think it's too close to call, which personally I would.

[PhilKing]

Phil, on 2013-March-14, 09:25, said:

This was the actual matrix of the results.

RESULTS OF BOARD 15

SCORES MATCHPOINTS NAMES
N-S E-W N-S E-W

620 8.00 0.00 2-Linsenbard-Robbins vs 8-Brilliant-Weiss

Not so Brilliant - headline writer's dream.

[JLOGIC]

I am a broken record on stuff like this at this point, but seriously just don't think about the field ever. "The field" obscures you from your real goal, use your expert judgement and decide how often are they going down. Yeah, imagine that the main concern on whether to X or not is to decide how often they are going down!

Likewise, on play or defense problems, your primary objective is to use your expert judgement to figure out what their hands are likely to be.

Yes, the field can be a secondary concern on close decisions, but people don't use it that way, the use it as a way to cop out or rationalize not doing their primary goal. All we need to know is generally doubling them and they make it costs more than doubling them and beating them one (exception is in true protect your partscore equity spots, but even then you never know that you were making or that their bidding was abnormal), so you want to be more than 50 % to double something, usually I would imagine 3/5ths or 2/3rds of the time. Other than that, have at it.

If anyone ever starts thinking of what the field is doing before thinking about the bridge aspects of the hand then stop yourself. It is better to never think about the field, seriously.

[lalldonn]

Phil, on 2013-March-14, 09:25, said:

Doubling moves you from a 69% board to a 100% board, although if they were to make it, you go from a 37% board to a zero.

This kind of exemplifies the point IMO. Even though there was a similar amount to gain and lose, to win at MPs you can afford some 37% boards but you can not afford zeros.

[Free]

I thought this was quite an obvious pass. We hope to defeat the contract, but that's not sure at all, therefor I wouldn't Dbl. And sacrificing is completely insane.

[han]

lalldonn, on 2013-March-14, 11:07, said:

This kind of exemplifies the point IMO. Even though there was a similar amount to gain and lose, to win at MPs you can afford some 37% boards but you can not afford zeros.

I don't understand your post. Are you less likely to win the event if you have a 50% chance to win 37% on the board and a 50% chance to lose 37% on the board? I can see that this is true if you expect to win the blue ribbon by a 2-board margin, but in general I'd say that this is not true.