[helene_t]

Lu, you are making bridge much more complicated than it already is.

It is true that Lawrence (and everyone else for that matter) recommend more aggressive overcalls at matchpoints than at IMPs. And of course more aggressive balancing.

But that is when he is discussing borderline hands where several actions would be sensible and it's just that one action has a small edge at MP and a different action has a small edge at IMPs.

You won't lose much if you just simplify things by ignoring the scoring. Unless you are a top player, there is so much scope for improvement that is way more significant than scoring considerations.

Besides, if you play matchpoints in a weak field (and by weak I mean everything that isn't worth vugraphing on BBO), it becomes more similar to IMPs. This is because the frequency tables are likely to contain lots of different scores, so a difference of 10 points is likely to translate into very few matchpoints. Say you have a choice between
1) a 80% make and 2) a 60% make with an overtrick. In a strong field we have all learned that you go for the overtrick. In a weak field you might as well play safe since lots of other pairs will be in a partscore or collecting some 300 penalty or going down in a slam or w/e.

And even if you are a top player, you certainly shouldn't play different systems at different scoring.

[babalu1997]

helene_t, on Jan 31 2010, 07:29 AM, said:

Lu, you are making bridge much more complicated than it already is.

It is true that Lawrence (and everyone else for that matter) recommend more aggressive overcalls at matchpoints than at IMPs. And of course more aggressive balancing.

But that is when he is discussing borderline hands where several actions would be sensible and it's just that one action has a small edge at MP and a different action has a small edge at IMPs.

You won't lose much if you just simplify things by ignoring the scoring. Unless you are a top player, there is so much scope for improvement that is way more significant than scoring considerations.

Besides, if you play matchpoints in a weak field (and by weak I mean everything that isn't worth vugraphing on BBO), it becomes more similar to IMPs. This is because the frequency tables are likely to contain lots of different scores, so a difference of 10 points is likely to translate into very few matchpoints. Say you have a choice between
1) a 80% make and 2) a 60% make with an overtrick. In a strong field we have all learned that you go for the overtrick. In a weak field you might as well play safe since lots of other pairs will be in a partscore or collecting some 300 penalty or going down in a slam or w/e.

And even if you are a top player, you certainly shouldn't play different systems at different scoring.

i again disagree helene, but the question of systems perhaps should be moved to another thread.

Playing precision, open 1d, the guy has limited his hand, answers are changed.

Playing SA, his range is huge, let us say 11-18, answers are changed.

I get genereally better scires at matchpoints with 5 card majors and better at imps with 4 card majors even in the palooka field.

Sometimes i get an undeserved score in matchpoints because we were playing in a field of imps bidders, sometimes I get a few imps because the imps bidders were bidding game when they should not.

So i just try to figure out whether the bad score was the result of something partner and i did, and move.

i do not plan to graduate from the free tourneys and go play the reisinger, so it is ok.

As for scoring, why change it?

the 90 percent who like imps will and do open their own tables.
the tds whose 90 percent of membership prefer imps are free to set their tourneys as they wish.

Let them do so.

As for me, ourt experience has been, when we sit at the main club and open a matchpoints table, we get much much better opposition than when we open imps.

Matchpoints scares many a bbo expert.

Very few people still play rubber bridge at bbo, why not change the scoring and compare with some par value so that the imps bidders can now enjoy a rubber scoring table?

I say that the folks who like to play rubber bridge find each other, mark each others names and life goes on...

[helene_t]

babalu1997, on Jan 31 2010, 05:23 PM, said:

I get generally better scores at matchpoints with 5 card majors and better at imps with 4 card majors even in the palooka field.

Funny, I think most would say it's the other way round.

5-card majors is generally better than 4-card majors for slam bidding (except when you open a minor suit and opps preempt over it) which is a bigger edge at IMPs than at MPs.

4-card majors lets you find your 4-4 fit faster which is especially an advantage in part score battles, and sometimes the less revealing auction gives you an overtrick. Of course the 4-card major openings can also sometimes mess up opps' constructive bidding, and the less revealing auction sometimes allows you to make an unmakable game contract.

Lawrence wrote in his 2/1 workbook that he thought the pros and cons of 5-card majors roughly cancel each other out for all purposes other than slam bidding. If he is right, everyone should play 5-card majors, but if you find 4-card majors more fun and easier to learn you would be more likely to let that be decisive and not bother learning 5-card majors if you mainly play matchpoints.

Quote

the 90 percent who like imps will and do open their own tables.

Yeah I wonder why as I personally prefer matchpoints. To some extent it is just the fact that IMP is default and people don't make a conscious choice. But also I think IMP is more prestigious in some circles because club games are usually matchpointed while serious competition is more often IMPs.

Quote

Very few people still play rubber bridge at bbo, why not change the scoring and compare with some par value so that the imps bidders can now enjoy a rubber scoring table?

IMPs and matchpoints are similar in that most decisions will be the same - it is only in borderline cases that one action has an edge at MPs and the other at IMPs. Rubber bridge is a completely different game. Say you need 60 points to reach the rubber, then you may just open 3♦ with 18 HCPs. Or raise partner's 15-17 1NT opening to 2NT with 14 HCPs. Or pass partner's 2♣ response to 1NT when you only need 40 points - you probably shouldn't play Stayman in that situation.

Most club players barely know the difference between MP and IMP strategy but they can play adequately anyway. Some experts have wicked ideas about matchpoint strategy too, IMHO, but of course I could be the one who is mistaken People who play rubber bridge without knowing the difference between rubber and IMP strategy would do completely absurd things all the time. Like raising a 2NT opening to 3NT when they only need 70 points for game.

Quote

Sometimes i get an undeserved score in matchpoints because we were playing in a field of imps bidders, sometimes I get a few imps because the imps bidders were bidding game when they should not.

You get the "undeserved" score because some people in the field make silly mistakes. It is very unlikely to be related to the scoring.
Say your p bids an invitational 2NT. You are vulnerable and you judge 3NT to be 45%. So you would have accepted at IMPs but you decline because it's MP. Then you see than some people in the field have bid 3NT and went down.

First of all, if the chance was really 45% then this will work against you 45% of the time so the edge is small. But more likely, something else happened:
- given the info that the other players had, the chance was actually 60% so they were right in bidding it but were just unlucky (or played it badly).
- given their info the chance was actually 30% so they shouldn't have bid it anyway, even if they thought it was IMPs.

[hotShot]

The main difference between MP and IMPs is that at MP each board has the same weight. A boring flat board has the same weight that a close slam makable only on a triple squeeze.
Many good player prefer IMPS at BBO because they can score many points at difficult boards, and can relax during the simple ones.
Many average player prefer IMPs because a lucky board can help their score a lot, while at MP the sum of small losses has a much bigger weight that their good board.

BBO uses XIMPs. They are closer to MP than simple IMPs.

[helene_t]

hotShot, on Feb 1 2010, 03:18 PM, said:

BBO uses XIMPs. They are closer to MP than simple IMPs.

What do you mean by "simple IMPs"? Butler?

XIMPs is similar to Teams. Butler is a little different.

[hotShot]

At IMPs you get nothing for 10 point difference.
At XIMPs your score is compared with several other scores and averaged over these. The 10 points more you have over some, can make 1 IMP more difference compared with others. So you will see that a 10 point difference can give you a faction of an IMP more at XIMPs than those who have 10 points less. Of cause not always, but sometimes.

[shyams]

hotShot, on Feb 1 2010, 02:34 PM, said:

At IMPs you get nothing for 10 point difference.
At XIMPs your score is compared with several other scores and averaged over these. The 10 points more you have over some, can make 1 IMP more difference compared with others. So you will see that a 10 point difference can give you a faction of an IMP more at XIMPs than those who have 10 points less. Of cause not always, but sometimes.

I think the fractions happen due to other results and not caused by the 10 pt differences.
Suppose we had a deal where 4♠ makes 4 and 3NT also makes 4. Say 6 out of 16 tables play 4♠ and the remaining play in 3NT. If all tables make 10 tricks, the cross-IMP score is ZERO for all tables.

[helene_t]

True, HotShot, but you have to see it this way:

Suppose you get 420 and the competition is 50% likely to get 400 and 50% likely get get 430. This means that you have a 50% chance of winning 1 IMP, iow your average win is 0.5 IMP.

At XIMPs, in a large field, you will actually get something close to 0.5.

At teams (which is another word for XIMPs with only two tables), you will either win 0 or 1 IMP. Your expectation is 0.5 IMP.

You should base your decisions on expectation so the XIMP strategy is identical to the teams strategy.

[hotShot]

Seems we are very close in our perception. Perhaps you would agree that an overtrick counts more:
MP>>XIMPs>IMPs.

[helene_t]

No, an overtrick counts exactly the same. On average, it is. Of course it could count a fraction in XIMPs and it won't count a fraction in teams. So in teams the fluctuations are bigger. More generally, the bigger the field the smaller the fluctuations.

Your XIMP score is like an average of a lot of team matches, each being played against a different table. So the expectation is the same. The variance is different.

[hotShot]

Well the tourney ranks depend on the fractions, especially midfield.
Taking a small extra risk can make a difference.
Lets say they variance is a factor there.

[helene_t]

hotShot, on Feb 1 2010, 05:16 PM, said:

Lets say they variance is a factor there.

I suppose it could be. Depends what your objective is.

I was assuming that your objective is to maximize your long-term IMP average. It appears to make very little difference in a teams tournament whether you maximize VP or IMPs.

You may have a preference for high variance (if you are underdog or if you need to improve your score) or for low variance (if you are overdog or you need to preserve your score).

[pirate22]

ty all for inputs---when i originally submitted my query,
the bidding went ply sayc 5cm and 1 d=min 4 cards.....

1cl--1sp
2sp--3d my pard shld have now 5 sp and a diamond suit(4) may have a factor,and as i had a heartfactor with diam support-i was also protecting my Kx factor in clubs--and elected to bid 3n/t (knowing we shld have a 5x4 spade fit.not always the case---so many players if they respond 1d over 1cl the 1cl assumes wrongly that the 1 d bidder has no 4 card major.this i hAVE FOUND OUT TO MY COST. SO THEYBID the spade first,and then bid diamonds,

as it happened my pard had 5 spades and 4 diamonds,and either contract was safe
regards

[babalu1997]

pirate22, on Feb 14 2010, 12:54 PM, said:

ty all for inputs---when i originally submitted my query,
the bidding went ply sayc 5cm and 1 d=min 4 cards.....

1cl--1sp
2sp--3d my pard shld have now 5 sp and a diamond suit(4) may have a factor,and as i had a heartfactor with diam support-i was also protecting my Kx factor in clubs--and elected to bid 3n/t (knowing we shld have a 5x4 spade fit.not always the case---so many players if they respond 1d over 1cl the 1cl assumes wrongly that the 1 d bidder has no 4 card major.this i hAVE FOUND OUT TO MY COST. SO THEYBID the spade first,and then bid diamonds,

as it happened my pard had 5 spades and 4 diamonds,and either contract was safe
regards

maybe you can have a look at the walsh diamond convention, and perhaps move this to another thread.

http://www.bridgehan...d_Responses.htm