[virgosrock]

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try this one. Lost $4.37 at 0.5 cents a point. Whatever takeout I moused over showed 10+ points.

GIB software bids anything. No controls/protection built in to minimize losses.

vrock

[smerriman]

( Ignore everything I wrote )

[virgosrock]

smerriman, on 2017-October-27, 15:54, said:

Good double by GIB. You can't base results on a single hand.

I ran a simulation based on 500 hands where North held exactly that hand, East would open 1♣, West would respond 1♥, and East would raise to 2♥. I even assumed West would pass 2♥ when holding 12 total points - in reality, West would bid some of that time so this is the absolute worst case.

Assuming best play and defense:

Making +2: 1
Making +1: 23
Making =: 103
Down 1: 142
Down 2: 98
Down 3: 90
Down 4: 35
Down 5: 7
Down 6: 1

Working out the numbers, that's an expected gain of $2.57 to the defence if you don't double; $4.37 if you double.

And before you ask, GIB isn't even simulating to come up with the double. That's the book bid made by a basic robot - a simulation would only have confirmed it was correct to begin with.

Seriously, these are valuable insights (regardless of simulation results) and I thank you for same. One thing to add here is if partner takes out it is NOT 10+. All bids I looked at were 10+.
AND stronger hand is on GIB's left.

vrock

[steve2005]

smerriman, on 2017-October-27, 15:54, said:

Good double by GIB. You can't base results on a single hand.

I ran a simulation based on 500 hands where North held exactly that hand,

I question your simulations. South on bidding can't have any defensive tricks.
+1 looks more likely than your simulation.
Maybe you get -1 not worth risk at imps/money bridge.
If popped a gasket can take huge risk a mp.

[The_Badger]

That's one double no sane, advanced player would make. You've already shown your hand as North, and the only reason I would double is a state-of-the-match/state-of-a-pairs matchpoint evening in sheer desperation to gain some points.

Anyone with an iota of bridge intelligence knows that doubling a two level major suit contract is akin to hara kiri except if you can absolutely see that it's going down.

Partner will have diddley squat to help you...as he did on this hand.

[smerriman]

steve2005, on 2017-October-28, 08:14, said:

I question your simulations. South on bidding can't have any defensive tricks.

Argh, I'm an idiot. I was surprised originally too but thought I had double checked things. Forgot to put a lower limit on West's point range

making +1: 68
making =: 186
down 1: 168
down 2: 65
down 3: 11
down 4: 2

Not doubling = 16 cents to the defence; doubling = $4.27 to the declarer.

So, I'm completely wrong. Thanks for correcting me.

If GIB were able to simulate in this situation it probably wouldn't have doubled too.

[steve2005]

smerriman, on 2017-October-28, 13:30, said:

If GIB were able to simulate in this situation it probably wouldn't have doubled too.

What's to simulate?! Gib overcalled a strong NT (so partner is in charge). Sure Gib's a max but that is no reason to go insane! It's a 2-level contract where opps have an 8-9 card fit that they freely bid without the A or K. They are often gonna make it. If it's down take the 100.

[smerriman]

That's the point - the book bid is wrong and should be fixed, but advanced GIB, if simulations had been turned on for the double (perhaps they aren't?) should have been able to figure that out and correct its mistake.

[johnu]

steve2005, on 2017-October-28, 20:43, said:

What's to simulate?! Gib overcalled a strong NT (so partner is in charge). Sure Gib's a max but that is no reason to go insane!

In defense of North's double, sometimes partners aren't paying attention and don't notice that you have a rockcrusher. Double is necessary in case partner has enough for game.

[virgosrock]

steve2005, on 2017-October-28, 08:14, said:

I question your simulations. South on bidding can't have any defensive tricks.
+1 looks more likely than your simulation.
Maybe you get -1 not worth risk at imps/money bridge.
If popped a gasket can take huge risk a mp.

you are my hero steve2005

vrock

[virgosrock]

smerriman, on 2017-October-28, 13:30, said:

Argh, I'm an idiot. I was surprised originally too but thought I had double checked things. Forgot to put a lower limit on West's point range

making +1: 68
making =: 186
down 1: 168
down 2: 65
down 3: 11
down 4: 2

Not doubling = 16 cents to the defence; doubling = $4.27 to the declarer.

So, I'm completely wrong. Thanks for correcting me.

If GIB were able to simulate in this situation it probably wouldn't have doubled too.

well smeeriman you said it yourself you have provided so much valuable info thus far we forgive you
Thus the new Rule should be "Double to show 18hcp and penalty only if stronger opponent is to your right. If GIB partner takes out it is NOT 10+. Is 0+"
And this brings me to my pet peeve. Were the Rule makers experienced bridge players? This particular incident says NO. Steve2000 still my hero.

vrock