Open light?

[Guest Jlall]

I think you should all try an experiment. Open all 10+ point hands with 5 spades at your next club game when you are NV. Don't tell your partner you are going to do this. I bet collectively you will get very good results.

 

Opening a hand like this just puts you in a ton of situations where you can go -50 or -100 instead of minus something bigger, or (less frequently) where you can go +120 or +110 instead of +50 or +100. This will happen far more imo than going down because you get too high in a constructive auction.

[Apollo81]

LOL

 

I think I know this hand; is this from the Silver Spring sectional? We opened a 10-12 NT with it and played in 2N after an..uhh..amusing auction.

[pclayton]

I think you should all try an experiment. Open all 10+ point hands with 5 spades at your next club game when you are NV. Don't tell your partner you are going to do this. I bet collectively you will get very good results.

 

Opening a hand like this just puts you in a ton of situations where you can go -50 or -100 instead of minus something bigger, or (less frequently) where you can go +120 or +110 instead of +50 or +100. This will happen far more imo than going down because you get too high in a constructive auction.

I will report back Wednesday.

[y66]

Is this from the Silver Spring sectional? Yes, Saturday morning game.

 

Pard (North) passed in first with that hand (per our agreed opening style), East opened 1N with a 14 count and something like xx KQ8x Ax AJxxx, I passed with AQ ATxx xxxx QT9 or so and then 2 more passes.

 

East's decision to open 1N won the board since we can make something our way. Don't think pard can balance there either (we play DONT).

 

This one goes in the + column for jlall's experiment.

[Guest Jlall]

This one goes in the + column for jlall's experiment.

Maybe, they will probably either X or overcall 2C, and you will probably get to 3N, but you will probably make it given that they have bid.

 

See Adam, sometimes you get to game opposite a 12 count and make when you just have 11!!!

[helene_t]

Apparently, if I'm playing with Csaba or Helene, as I sometimes do, I might have to rethink this and Pass - but I usually play somewhat unusual systems (e.g. EHAA) with them so I might have other options - it probably qualifies as a 1NT (or 2♠) opener.

No, opening this hand is fine if you

- have discussed it with p - I, for one, am happy to agree to open this one when nonvulnerable in 1st seat, even playing standard - or

- have not discussed it but believe in Justin's experiment.

 

It's just that I was assuming that we in principle open on the basis of rule of 20. We can agree on something else of course, then we might even cater for lighter openings.

 

Anyway, this is all academic since this is a wtp 1NT opening playing EHAA.

[Cascade]

I open - its not minimum

[rogerclee]

Playing a middle-of-the-line 2/1 style, I would open this 1♠ only NV at MPs. I am a big fan of opening 1M whenever possible at this form of scoring and vulnerability.

[Apollo81]

This one goes in the + column for jlall's experiment.

Maybe, they will probably either X or overcall 2C, and you will probably get to 3N, but you will probably make it given that they have bid.

 

See Adam, sometimes you get to game opposite a 12 count and make when you just have 11!!!

we were +180 which was 17/21, +150 would be 13.5, 400 & 430 are 18 & 20 respectively

[skjaeran]

I open - its not minimum

Absolutely agree. I'd never dream of passing this... had to be a nightmare, and we really lost the board after i passed.

[awm]

I think you should all try an experiment. Open all 10+ point hands with 5 spades at your next club game when you are NV. Don't tell your partner you are going to do this. I bet collectively you will get very good results.

 

Opening a hand like this just puts you in a ton of situations where you can go -50 or -100 instead of minus something bigger, or (less frequently) where you can go +120 or +110 instead of +50 or +100. This will happen far more imo than going down because you get too high in a constructive auction.

So I thought this would be a good subject for bridgebrowser, especially since Justin is suggesting this to everyone in the B/I area, so it's not like he's saying this will only work if you are a world class declarer or will only work if you play some weird system.

 

I looked for hands where dealer has 5♠(332) shape, 11 hcp exactly, and 3 controls (in order to eliminate very quacky hands or the AK+A combo that a lot of people upgrade). This also happens to specify 25 ZAR points (making Ben happy I suppose). I specified the dealer to be NV, and looked for the average results at both MP and IMPs.

 

MPs:

 

Initial Pass happened 1719 times, averaged 48.66% with standard deviation 0.67.

Open 1♠ happened 954 times, averaged 52.02% with standard deviation 0.99.

 

So it looks like opening 1♠ is a small net winner at MP. Of course, these things are always biased a little bit because of people who have special systemic agreements, but I suppose that these are probably a small minority of the BBO field.

 

IMPs:

 

Initial Pass happened 1924 times, averaged +0.05 IMP with standard deviation 0.12.

Open 1♠ happened 1200 times, averaged -0.10 IMP with standard deviation 0.17.

 

It seems like passing is a small net winner at IMPs, although the difference is extremely small and quite close to the margin of error.

 

There were a few other opening bids (i.e. 1NT presumably weak, 2♠) but not enough of them to really conclude anything.

[jdonn]

Initial Pass happened 1719 times, averaged 48.66% with standard deviation 0.67.

Open 1♠ happened 954 times, averaged 52.02% with standard deviation 0.99.

Speaking as someone who doesn't normally open this hand, isn't that two different ways of saying that there is a 95% chance opening it is better than passing it?

[helene_t]

I think Adam means standard error, not standard deviation. Standard deviations on matchpoint results are typically 30% or such, corresponding to a standard error of some 0.7% by 1719 samples and 1% by 954 samples, this is roughly consistent with Adam's numbers.

 

As for Josh's conclusion, no, if opening scores 52% on average then the probability that opening is better than passing is not far from 52%. Somewhat more than 52% because the MP scores for the two decisions will be correlated, i.e. a good players tends to score above 50% whether he opens or passes.

[Gerben42]

 

Initial Pass happened 1924 times, averaged +0.05 IMP with standard deviation 0.12.

Open 1♠ happened 1200 times, averaged -0.10 IMP with standard deviation 0.17.

 

What about 1NT? :)

[jdonn]

As for Josh's conclusion, no, if opening scores 52% on average then the probability that opening is better than passing is not far from 52%. Somewhat more than 52% because the MP scores for the two decisions will be correlated, i.e. a good players tends to score above 50% whether he opens or passes.

What I meant was there is a 95% chance that opening it averages a better result in the long run than passing it, given that both results are 2 standard deviations away from 50%. I wasn't saying it will work better 95% of the time. Of course if they aren't standard deviations, as you say, then never mind.

[helene_t]

What I meant was there is a 95% chance that opening it averages a better result in the long run than passing it, given that both results are 2 standard deviations away from 50%. I wasn't saying it will work better 95% of the time. Of course if they aren't standard deviations, as you say, then never mind.

Sorry I misunderstood. Your conclusion is correct, then.

 

(Strictly, confidence at the 95% significance level is not the same as a 95% probability but you probably need to be a statistician to be exited about this)

[awm]

Yes, the conclusion is that opening is better than passing on these hands at MP. It seems there are enough trials (and enough difference) to be pretty sure of this. The conclusion at IMPs is the opposite, although this is not quite as certain.

 

Of course, there are always some issues with this kind of bridgebrowser test. In particular there is the question of whether good pairs (i.e. pairs with a lot of partnership experience and/or pairs consisting of two good players) are more likely to open or pass than random pickups. For example, I am sure that a high percentage of people who are playing a strong club system open and these pairs probably average better results (because they have more systemic agreements than average and are unlikely to be novices if they are playing strong club). So there is some inherent bias, but I suspect that the vast majority of pairs on BBO are playing something pretty standard and are not long-standing partnerships, so hopefully this effect doesn't have too much impact. I may try a few tests to measure this effect later tonight.

 

I can't answer Gerben's question because: (1) there were only something like 8 1NT openings on these hands so the results will be very inaccurate (2) anyone who is playing weak NT probably has a bit of an edge on the field (a high percentage of these are established partnerships, although surely a few are pickup british pairs playing acol).

[han]

Can't you restrict the search to people who's rating is 50-51 or something like that?

[Guest Jlall]

Not surprised by Adam's results (since they backed up what i said lol), but just want to add if you are a good player I think that your result from opening this hand will be even higher than your average result (so if you rate to get 60 % every board, I think you will get 70 % on average from opening this hand). This is because your superior card play skillz will get you out of trouble a lot when you are in some stupid contract (this happens a lot to me lol) and because by creating a competitive auction you are less likely to make a big mistake than the opps. IMO those are the 2 biggest areas where you can gain MP in general.

[neilkaz]

With no aces, this 5332 11 count is just a bit weak for me to open inspite of me loving to get the ♠ suit in quickly. Give me the 10 of ♠ and I'll open this playing SAYC or 2/1

 

.. neilkaz ..

[ArtK78]

Interesting discussion.

 

When I first saw this problem (today) I voted to open. It was almost a "wtp." Experience tells me that opening this hand is right. Jlall says his experience is the same. The bridgebrowser result confirms this in a statistically significant manner (at matchpoints).

 

I would not get upset with a partner who chose to pass this hand, I just don't think pass is the winning action.