Your thoughts on this potential study?

[MickyB]

I forgot to add that undisciplined preempts work well when non vul. Would be more careful when vulnerable.

 

In before CSGibson flips

[CSGibson]

In before CSGibson flips

 

I had decided to let it be - I tried to keep the thread headed in a useful direction for me and not on these stupid tangential points, but one admonishment is all I had in me.

[Mbodell]

Maybe it would be useful to email Richard Pavlicek so he could run something along the lines of "preempt with 6carder at one table, pass at the other" on his database.

He did similar studies already, link to one: http://www.rpbridge.net/9x13.htm

 

I agree this style of study could be useful. I was thinking of http://www.rpbridge.net/9x16.htm which is open 1H versus 4H (4H better in small sample size). But you might want to know preempt at one table versus more passive action at the other (lower preempt/pass) compared to preempt at one table compared to stronger action at the other (higher preempt, opening 1 bid) and compare those. As others have suggested if there is a pair in question you want to study (or even a set of pairs) for this sort of thing you probably also want to look at hands where the same action is taken at both tables because a wide ranging style should be behind a more constrained style when both take the same action.

 

Of course, there are second and third order effects and some bidding style might be good primarily through the negative inferences when it doesn't come up (which could happen in the bidding or the play). The hope is these would be smaller in effect than the "main" bid being studied, but that isn't clear. For instance a bid that is -0.1 IMPs/hand when it comes up but adds +0.01 IMPs/hand when it doesn't come up through negative inference could be a big winner when its frequency causes it to only come up on 1-2% of hands. There is also how well the style/bid fits into the rest of the system (it could be wide ranging preempts are good in a 2/1 context but bad in precision - or vice versa, say).

[MrAce]

Maybe it would be useful to email Richard Pavlicek so he could run something along the lines of "preempt with 6carder at one table, pass at the other" on his database.

He did similar studies already, link to one: http://www.rpbridge.net/9x13.htm

 

Richard Pavlicek himself is one of the most aggressive players I have ever seen. I partnered him online a lot and off line in Reisinger bam. I looked like conservative compared to him when it came to preempts.

 

I agree with Philking that simulations are silly and that preempts are all about pressure. If you look at the pars both side can make it will lead you to inaccurate conclusions.

[PhilKing]

If anyone wants to do the work I have filtered out 90 hands where one side opened 3♣ and the other did something else.

[hotShot]

DD Simulations are tricky.

You need to be absolutely clear about what question you want to get answerd and once the simulation has finished you need to recheck if the result you got is really an answer to the question you wanted to ask.

 

It is possible to answer the question what percentage opps could make game/slam on deals you would preempt. (But it won't tell you if your preempt applies any pressure on opps.)

If that percentage is "low" your preempt style might be to solid.

 

You could ask for the percentage of preempts in minors where your side could take e.g. 7 tricks.

If that percentage is "low" your preempt style might be to aggressive.

 

If you ask for the percentage where opps find their best spot after your preempt. DD simulations can't give you the answer.

As for this study DD-Simulations don't seem to be very helpful.

 

But I think it is obvious that a preempt is reducing the bidding space and by that limiting the amount of information that can be transported by bidding. This will usually result in less accuracy in opps bidding, giving them an opportunity to guess wrong.

[NickRW]

Any methodology that suggests the use of DD analysis is, in my opinion worse than useless - preempts are all about pressure, and even world-class pairs underperform in this area

 

I agree. DD results are reasonable, if not 100% perfect, given that you know what the contract is (should be). The whole point of a pre-empt is that the proper contract will not always be reached.

 

Another point is that you have to factor in the matter of, when opps do find their contract, you have leaked considerable information about your shape. They might now make their contract when they wouldn't have without the leakage.

 

And yet another point is that pre-empts sometimes propel opps into making slams that they might well not have bid under their own steam.

 

Not saying that aggressive bidding, pre-emptive or otherwise, is not winning bridge. Just that there are a *lot* of factors to weigh up.

 

Nick

[Zelandakh]

One obvious way of using DD would be to run an auction for the hands manually and then assume the DD result for the resulting contract. Obviously not perfect either but faster than also trying to work out the play manually. Could you produce the hands as an East set and a West set plus opponent bidding should one of our pairs feel up to trying this as a challenge, Phil?

[helene_t]

You could also let some SD software like Jack play a zillion boards between three or four teams, playing the same system but different preempt style.

[cherdano]

You could also let some SD software like Jack play a zillion boards between three or four teams, playing the same system but different preempt style.

Which would tell you very accurately whether it is beneficial to preempt against Jack if your bidding works exactly like Jack's...

[FM75]

Which would tell you very accurately whether it is beneficial to preempt against Jack if your bidding works exactly like Jack's...

:) Which is why I suggested that an effective study would need to be done against a range of competitive bidding systems. Of course, your results likely would vary against each, which would show you when you get your best results, and when you get your worst - or conversely, how best to compete from the set of systems measured, against the preemptive style.

[rhm]

I do not quite understand why it would be beneficial to restrict this question to a specific pair.

 

Richard Pavlicek published results from top level tournament play at http://www.rpbridge.net/rpme.htm where one room opened with 4M and the other with 1M

 

This could be extended to other preemptive scenarios.

Of course this does not answer all questions, but I doubt that any study will ever be conclusive.

For example you do not know from these results what happens when a preempt is obvious, but one pair is better placed, because its preemptive tendencies are more conservative.

 

Undoubtedly, just like opening bids restrictions on preempts have loosened over the years.

What puzzles me is that there is a corresponding trend to shy away to take the money.

This remarkable reluctance can only reinforce the trend to preempt on thin air.

The success of the Kranyak team in the trials to the Bermuda Bowl in Bali was in part due to the fact that they did not have this reluctance to play for penalty.

[hv=pc=n&n=sat7hkjt4da953c54&d=w&v=n&b=12&a=3cp4cdp?]133|200[/hv]

 

What do you bid?

 

This time it was Kranyak, who preempted and Wolpert, who raised the preempt.

A reigning world champion bid 4♥ and played it there.

In the other room with no preempt 6♦ was bid and made

A simple PASS and an easy defence would have netted six undertricks and 1400.

Well, if even a world champion can not take the money when the contract is six down, I am not surprised that preempts get weaker by the day.

 

Rainer Herrmann

[helene_t]

Which would tell you very accurately whether it is beneficial to preempt against Jack if your bidding works exactly like Jack's...

True, if the question is if Kit's style works well for Kit then Jack is obviously irrelevant.

 

But a Jack study is, at least, easy to interpret. You can avoid confounders (aggresive preemptors may tend to have strengths or weaknesses in specific other areas) and take related effects into account (a pass caries a different meaning for an aggresive preemptor than for a disciplined preemptor). You can also avoid a possible gain from inadequate disclosure (partner knows your preempt style better than opps do).

[hotShot]

I do not quite understand why it would be beneficial to restrict this question to a specific pair.

 

Richard Pavlicek published results from top level tournament play at http://www.rpbridge.net/rpme.htm where one room opened with 4M and the other with 1M

 

This could be extended to other preemptive scenarios.

Of course this does not answer all questions, but I doubt that any study will ever be conclusive.

For example you do not know from these results what happens when a preempt is obvious, but one pair is better placed, because its preemptive tendencies are more conservative.

 

Undoubtedly, just like opening bids restrictions on preempts have loosened over the years.

What puzzles me is that there is a corresponding trend to shy away to take the money.

This remarkable reluctance can only reinforce the trend to preempt on thin air.

The success of the Kranyak team in the trials to the Bermuda Bowl in Bali was in part due to the fact that they did not have this reluctance to play for penalty.

[hv=pc=n&n=sat7hkjt4da953c54&d=w&v=n&b=12&a=3cp4cdp?]133|200[/hv]

 

What do you bid?

This time it was Kranyak, who preempted and Wolpert, who raised the preempt.

A reigning world champion bid 4♥ and played it there.

In the other room with no preempt 6♦ was bid and made

A simple PASS and an easy defence would have netted six undertricks and 1400.

Well, if even a world champion can not take the money when the contract is six down, I am not surprised that preempts get weaker by the day.

 

Rainer Herrmann

 

What to bid now is irrelevant, as the problem was caused by North pass last round.

A bidding system that forces North to pass his 12HCP balanced hand with support or at least tolerance for the unbid suits, definitely puts you in an disadvantage playing against preempts.

[rhm]

What to bid now is irrelevant, as the problem was caused by North pass last round.

A bidding system that forces North to pass his 12HCP balanced hand with support or at least tolerance for the unbid suits, definitely puts you in an disadvantage playing against preempts.

Strong stuff, considering that (Bocchi-Madala) are the current Bermuda Bowl winners and on anybodys shortlist for the best pair in the world.

I at least have much more sympathy for the initial pass than for the second bid.

 

Rainer Herrmann

[beatrix45]

The advice I once got from a white haired old guy named Oswald Jacoby was to preempt aggressively (or even psyche) against better opponents and to play straight down the middle against equal or weaker ones. The idea was to make the better players guess. They guess very well but do worse than if you just leave them alone. Of course, Jake himself usually played down the middle (unless he was behind and needed a board) since from his point of view there were no better players.

 

The pair in question is actually a (slightly) lesser pair at the very top levels of the game. I don't see statistical analysis as the way to go here. There are too many hard to measure variables involved (state of the match, quality of the opponents, feel of the table, etc.). Examining hand records from the round of 32 on of major championships might prove to be useful though.

[Lorne50]

Brian Senior published an analysis of the 1997 World Championships in Tunisia looking at all 2 and 3 level openers and comparing results for different meaning of the various bids. Frequency of each call was very low however but it may be worth looking at to give ideas about what to measure. The intro says he was planning to do it again at future events but I do not know if he did.