mentor/mentee disagreement

[PhilKing]

So, I made this thread...

 

http://www.bridgebase.com/forums/topic/60301-simulation-request/page__pid__726856#entry726856

 

One the example hand, out of 10,000 trials, it made game 41.62% of the time, which is well above the equity point, so that strongly supports just blasting game.

 

Does it?

 

If we were not allowed to invite, that would be true.

[dustinst22]

The thing with inviting, is that when you invite and the invite isn't accepted, you're about 40 pts a board worse off than if you just always passed 2. I've done some additional equity calculations.

 

Basically, at vuln, always passing 2 has an EV of 140.8, always bidding 4 an EV of 178.0, and being in 3 an EV of 102.7. If your invites are 100% perfect, your EV jumps up to 290, but being wrong at all, ever, hurts it quite a bit.

 

How are you calculating the EV for being in 3?

 

i.e. Being in 3 across any 15-17 hand? If this is the case, obv the EV won't be great because you'll be missing many games. I think to calculate the EV for invite you have to set the parameters to being in 3 across a minimum hand that opener won't accept with. Also, as Justin pointed out, opener will accept on many different types of hands (17 always, 16 sometimes, prime 15's occasionally). So plugging in a point value is not going to be very useful.

[PhilKing]

How are you calculating the EV for being in 3?

 

i.e. Being in 3 across any 15-17 hand? If this is the case, obv the EV won't be great because you'll be missing many games. I think to calculate the EV for invite you have to set the parameters to being in 3 across a minimum hand that opener won't accept with.

 

I did a short non-dd sim (32 hands) which suggested that partner was able to accept/reject very accurately.

 

In my method, I can invite and still stop in 2♥, which is obviously ideal.

[Wwchang]

Is Double Dummy analysis really the best way to determine if we belong in game?

 

Separate from this question, is the question of how well double dummy results compare to single dummy results. At least in the case of 4!h contracts specifically, Pavlicek's stats suggest they conform very closely.

[Wwchang]

I have some calculations on the other thread that suggest that blasting is about as good as random acceptance of invites, but if acceptance of invites is better than random, then inviting leads to a better overall result (caveat: does not take into account opposition bidding, and the simulation that was run does not exclude superaccept-type opening hands).

[TylerE]

Is Double Dummy analysis really the best way to determine if we belong in game?

 

In this situation, I think it's pretty dead on.

 

In partscores, DD tends to be a bit friendly to declarer (Get suits right 100% of the time), but in slams tends to favor the defense a bit (If there is a lead to beat it, it _will_ be found, even if odd and non-obvious at the table)

[aguahombre]

Is Double Dummy analysis really the best way to determine if we belong in game?

It is, indeed...if partner doesn't know what an acceptance looks like.

[mycroft]

...and if our opponents are perfect defenders...

 

Okay, and if we guess the Q 100%, and, and. Anybody have a feel as to whether declaring below DD is more or less likely than defending below DD?

[aguahombre]

...and if our opponents are perfect defenders...

 

Okay, and if we guess the Q 100%, and, and. Anybody have a feel as to whether declaring below DD is more or less likely than defending below DD?

At some point in our off-and-on Bridge history, we came to a conclusion about all this:

 

The theoretical expectations from perfect defense and perfect dummy play are all a big wash. If we make better (informed) decisions than the field we win, if we don't we lose.

 

Where we gain is in the knowledge that the bidding decisions were partnership decisions, some of our defensive errors were partnership errors, and we have avoided masterminding ---which annoys both of us.

[PhilKing]

...and if our opponents are perfect defenders...

 

Okay, and if we guess the Q 100%, and, and. Anybody have a feel as to whether declaring below DD is more or less likely than defending below DD?

 

There is little need for guesswork, since Pavlicek has compared top-level play with DD play over a large sample.

 

The defence is closer to par after trick 1, but often drop a trick on the lead (this maybe slightly bogus, since the lead sometimes only costs if declarer is also DD).

[Wwchang]

There is little need for guesswork, since Pavlicek has compared top-level play with DD play over a large sample.

 

The defence is closer to par after trick 1, but often drop a trick on the lead (this maybe slightly bogus, since the lead sometimes only costs if declarer is also DD).

 

on 4♥ contracts specifically, DD tricks averaged 10.01 and actual tricks averaged 9.99 over 8699 contracts. DD made 68.65% of the time, actual made 68.35%.

The difference is much larger for 3♥ contracts. There, average tricks were 8.41 DD and 8.49 Actual, with 3♥ making 52.82, and only 48.46 DD.

 

 

http://www.rpbridge.net/9x29.htm

[wank]

So, I made this thread...

 

http://www.bridgebase.com/forums/topic/60301-simulation-request/page__pid__726856#entry726856

 

One the example hand, out of 10,000 trials, it made game 41.62% of the time, which is well above the equity point, so that strongly supports just blasting game.

 

you quote a statistic and draw a random conclusion from it.

[Free]

I would transfer and pass. I don't have any intermediates in ♥, I don't have a shortness, I don't have an Ace,...

 

I wouldn't call inviting a mistake, but a matter of style. However, when you would invite with this hand, South shouldn't accept it! When you invite this hand, it means you play light invites, so you should accept heavy. South isn't heavy at all.

[Free]

So, I made this thread...

 

http://www.bridgebase.com/forums/topic/60301-simulation-request/page__pid__726856#entry726856

 

One the example hand, out of 10,000 trials, it made game 41.62% of the time, which is well above the equity point, so that strongly supports just blasting game.

Some people should really learn how to interpret statistics, or they should ignore them all together...

[RunemPard]

Mr. George...may we have the full hand. :) I have blasted texas on these hands in the past, and the only good results have been when the opponents belong in a making contract or unlikely game. So I am going to go with transfer/pass.

[diana_eva]

I would transfer and pass. I don't have any intermediates in ♥, I don't have a shortness, I don't have an Ace,...

 

I wouldn't call inviting a mistake, but a matter of style. However, when you would invite with this hand, South shouldn't accept it! When you invite this hand, it means you play light invites, so you should accept heavy. South isn't heavy at all.

 

Right. At these colors, I'd expect my partner to accept on any excuse therefore my invites are not light. On the given hand, with 3 aces, my partner would have accepted even if he had only 15 points. Is this really a bad game? Maybe not - but anyway, as Dustin mentioned before, there should be some agreement between partners so that they don't both stretch in such situations.

[mike777]

So, I made this thread...

 

http://www.bridgebase.com/forums/topic/60301-simulation-request/page__pid__726856#entry726856

 

One the example hand, out of 10,000 trials, it made game 41.62% of the time, which is well above the equity point, so that strongly supports just blasting game.

 

 

what is equity point

 

why is 41% well above it

 

 

why does that support, strongly support, blasting to game

 

--

 

 

Is there any argument for not bidding game above this equity point?

 

In other words do you 100% bid game above this equity point?

 

 

can we always know this equity point or is it often just a guess?

[mikestar13]

I disagree. The IMP equities favor bidding games that are well under 50%, or even under 40% to make.

 

Equally, I've gotten good results passing with very marginal invites. That's the other side of the coin. Basically at IMPs, especially vuln, you really don't want to be at Game-1. +110 vs -100 is a 5 imp swing.

 

 

Not correct for a normal novice game--the normal equities don't apply because both sides are quite likely going to drop tricks, and this is more likely to hurt the side that is facing the longer odds (making a 40% game requires better technique than making a 70% game). Texas is reasonable with the mentor as the no trump bidder, as he presumably is a good card player, but not the right thing to teach the mentee unless he is always partnered with good card players. I know that in my novice days, I played many more boards partnered with another novice than with an expert!

[nigel_k]

So, I made this thread...

 

http://www.bridgebase.com/forums/topic/60301-simulation-request/page__pid__726856#entry726856

 

One the example hand, out of 10,000 trials, it made game 41.62% of the time, which is well above the equity point, so that strongly supports just blasting game.

Even supposing that inviting is contrary to your religious beliefs, there are several unstated assumptions here:

 

1) Opener never has a super accept. In reality they sometimes do and those hands have to be excluded because you'll reach game under any approach.

2) Game either makes or is down one undoubled. Sometimes it is down two and/or doubled.

3) Opener has what a computer would call 15-17 balanced. In practice people upgrade 14 or 17 HCP hands a lot more than they downgrade 15 or 18 HCP hands. So the set of hands for opener in real life is weaker than the ones in your simulation

 

So if the simulation does have game making 41.62% of the time, that suggests to me that the best action at the table is either transfer and pass or invite.

[gszes]

Mr. George...may we have the full hand. :) I have blasted texas on these hands in the past, and the only good results have been when the opponents belong in a making contract or unlikely game. So I am going to go with transfer/pass.

 

The point of the discussion was what to do with responder's hand. How do you evaluate for ex is Kx xxxxxx xxx Kx the same as xx Kxxxxx Kxx xx? is one of these

two worthy of a texas and the other a simple jacoby and pass. At MP we invite dearly meaning we are a tad on the heavy side asking p to bid game with anything but a minimum. At IMPS where we push to bid game we invite freely which means we ask p to bid game only when they are close to maximum

(not strong enough to super accept). How does vulnerability affect your decision? These are the kinds of nuts and bolts decisions that help make

strong and enjoyable partnerships. Even if you are slightly on the wrong side

as long as both of you are happy with your p decision you will enjoy this great game of ours rather than having to reach for the pepto bismol every time you

see a dummy you feel was overbid or underbid (no matter the result).

 

For what it's worth, the three mentees were upset that I didn't create a poll because they were absolutely certain they were right. They were also quite

happy to see that an issue they felt strongly about had generated 40+

responses. I warned them before posting that there would likely be nothing

like a consensus because we are taught differently and that strongly affects

how we think about hands. TYTY all for your input.

[1eyedjack]

What Nigel_k said, but in addition:

Even if you don't upgrade 14 and 17 count hands, within the 15-17 range you are more likely to have 15 than 17.

 

From recollection, the 40% odd breakeven point for bidding vulnerable games is calculated by assuming that the contract will either make on the nose undoubled or go one down doubled. Other possible results would tend to elevate the break-even position slightly: You are more likely to be doubled if you are going two down than making an overtick, and if you are doubled then going down is quite a likely outcome, of which the odds of going more than one down are likely elevated.

 

I don't challenge the 40% rule - it is too well ingrained in the expert community and there will be other factors such as difficulty of finding the killing opening lead.

 

But there is one related factor that adds to the benefits of blasting game over inviting. It may not be sufficient to make it the right bid, but I throw it into the pot as it does not seem to have been mentioned elsewhere in the thread.

 

After a limited opening bid followed by invite and acceptance, you are at significantly elevated risk of being doubled if the cards lie unfavourably. Neither defender needs to have enough to defeat the contract on his own; it is sufficient that he can see that the suits are breaking badly, and he can rely on his partner to have any partnership high cards that he is missing, out of a known total pot. But if you blast game, for all they know you could have vailues in reserve to compensate for bad breaks, so that if the defensive values are evenly divided you are more likely to buy it undoubled even against bad breaks.