[hrothgar]

inquiry, on Apr 14 2006, 05:36 AM, said:

Sadly you fail to understand. My search does not find balanced 10-12 hands that open 1NT. It finds ALL BALANCED hands that are 10-12 hcp, and with bid analysis separates them  into each bid: pass, 1C, 1D, 1H, 1S, 1NT, etc (yes you find 2♦ bids and even more, just very few of those).

Its perfectly obvious what you're doing.
Its also readily apparent that this approach is flawed.

1. If a player opens 1NT on a balanced 12 count is his range 10-12, 12-14, or 13-15 with frequent upgrades?

As Josh and I already noted, the fact that someone chose to open 1NT (or 1C or whatever) with a balanced hand and 10-12 HCP doesn't necessarily mean that this was their agreement. The player making the opening could have psyched or misbid or whatever. This probably isn't as important for a mini-NT but could be quite significant for other types of openings. I return to my earlier example... If a player makes a 1NT of a 1♦ opening overcall holding

♠ AQJ2
♥ K
♦ K42
♣ KT732

how do you tell whether they are playing raptor?

2. You are examining balanced hands with 10-12 HCP in isolation from the rest of the system. Its entirely possible that the 10-12 NT opening will score quite well, however, the system as a whole will be net negative because the 1m openings are badly overloaded. The analysis that you propose can't measure any kind of negative inferences.

[inquiry]

Richard,

I appreciate the impossibility to use such bids as part of a system and being a problem. I appreciate not only your complaint here, but other complaints as well. Nevertheless, the way to do approach this and similiar studies is to be very blunt about the search and very encompassing and then use bid analysis (and the new plotting feature) to examine what is happening.

A reasonable question is:
How good (or bad) is it to open 1NT with a balanced hand and 10 hcp, when Vul?
same but when not vul?

Here 1NT might be a psyche, might be part of 8-10 nt, or might be 10-12. But it gives you data on how the 1NT bid works out. Bridgebrowser data seems to suggest that four card majors work better at matchpoint than opening better minor, but less well at imps (a study i did once). This does not seperate out the 1M opening that are systemic or table feel bid.

But the key part of my post was how to phrase large database searches. You simply HAVE to use the Bidding/HCP tab to set initial parameters and search from that page. Then the other trick there was shape issues, making sure no five card major, and limiting to first seat. The limit to first seat is necessary,,, (you can search by any seat, btw), if you want to be sure that passes are included in the mix (otherwise you will only get data for hands where the hand with 10-12 did not pass). For what it is worth, I take a lot of the "overall statitics" from bridgebrowser with a grain of salt, until the number of hands found is quite large. I seriously doubt there will ever be enough 10 or 11 hcp 1NT opening bids to draw a good conclusion. There are lots of 12 pt 1NT opening bids (part of 12-14 i guess).

[han]

inquiry, on Apr 13 2006, 09:36 PM, said:

Hannie, on Apr 13 2006, 09:10 PM, said:

inquiry, on Apr 13 2006, 04:51 PM, said:

Well, the solution here is something quite different. First thing I would do is use a large Bridgebrowser database of at least 4 million hands, and probably one with 29 million.

Second, I would restrict the search to first seat opening bids, for simplicity

Third, I would search for balanced hands with 10-12 hcp in first seat. This would be set on the Bidding/HCP tab, along with shape from 4333 to 5332, because this will speed up the search which will be quite slow anyway. I would also go the VIEW tab and check the box labelled "suppress main display" as this will spead things up considerably. Then go to the Bid analysis tab and choose that as an auxillary term. Finally I would go to the Bidding tab and set shape to 4333, 4432, and 5332  (also select that as auxiallary term), also choose 4 or fewer spades and hearts.

The I will go back to the bid Shape/hcp tab and press search.

Just like Pigpenz, you seem to be answering a question you haven't read.

Sadly you fail to understand. My search does not find balanced 10-12 hands that open 1NT. It finds ALL BALANCED hands that are 10-12 hcp, and with bid analysis separates them into each bid: pass, 1C, 1D, 1H, 1S, 1NT, etc (yes you find 2♦ bids and even more, just very few of those).

In addition, with bid analysis turned on, you can see how each bid did (on average), did. For example, "opening" with a pass averages a perfect 0.00 (i would bet), and you can "see" how the other bids do on the same hands. But more than that, you can "click" on the 1NT opening bids and see how opening 1NT with balanced 10 does, versus balanced 11 (the mean, sd are given). You can see after opening 1NT does the opening side do better declaring or defending, again with the plot routine?

Ben

BTW comparing me to pig probaby makes him angry with the comparison, and certainly does so to me.

I do understand your search plan. However, I fail to see how it solves any of the 3 problems that have been mentioned. I know that you are smart enough to understand those, so I conclude that you haven't read them.

I don't mean to compare you and pigpenz with eachother, just your responses in this thread.

[kenberg]

I think the answer to the question "Can you define and run a Bridgebrowser test that convincingly shows that one particular treatment is better than another" is "No". However, maybe it is possible to do something. I'll simply trust that what I suggest is technologically possible. If it isn't, it will be soon as the technology advances.


Let's consider 12-14 nt versus 15-17 nt.


First, select events of a certain type, for example acbl pairs tourneys.

Next, identify pairs who play in many of these.

Third, select a hand pattern or patterns that pretty much everyone would agree is opened 1NT if the point count is within the range.

Fourth, search on each of the chosen pairs to find out whether, in practice, they open hands in the 12-14 range, the 15-17 range, or some other range. An exact criterion could be set for this that would allow the occasional out of range call. This would be an operational definition of "plays weak/strong nt", independent of what they may actually say they play.


This is the easy part. Now to evaluate how it fares. I think that really it cannot be done. But something can be done. You can see how pair X does in the tourneys. Say the average 58%. You can see how they did on the hands that had the shape chosen above, and hcps in each of the two ranges. Perhaps these figures would be above 58%, perhaps below. You could then, with perhaps some confidence, say things such as "On balanced hands in the 15-17 nt range, it appears to cost if you are playing weak nts, since the weak no-trumpers who scored x% overall scored only y<x percent on the 15-17 balanced hands". Since I am not in advance certain that y would be less than x, it seems that this is not a totally trivial statement. In particlar there would be some sort of quantitative estimate of the cost of various agreements in various situations.


Of course it is very limited. The auction on unbalanced hands is affected by the NT range that you play, and this is very serious. The above would not address that at all. But science advances in small steps usually, and it seems that something could be said.


I apologize in advance if you find this non-responsive. I did read all the posts, and I don't believe I am a total moron. I really doubt the overall objective can be accomplished, but I think what I suggest has not, as far as I know, been done and I think it would be interesting.

k

[cherdano]

awm, on Apr 14 2006, 01:01 AM, said:

I think in order to do this you'll have to pick and choose your convention to evaluate very carefully. Ideally it should be one where:

(1) The ripple effect on the rest of the system is minimized.
(2) The caliber of player and whether they do this isn't very correlated.
(3) The "false positive" data arising from people actually playing a different method isn't too high.

The 10-12 notrumps fail pretty much all these tests.

One that might be a little closer to possible, is opening a weak 2♠ with 5332 distribution. It seems as though:

(1) Most people who open 2♠ on these hands still open 2♠ with six-card suits also. There aren't really any strong negative inferences based on failure to open 2♠ because not all hands with five cards necessarily qualify. The basic opening structure remains relatively intact.

(2) I see this kind of bid from really good players and really bad players. It's more a function of "aggressiveness" than skill I suspect.

(3) This is why I restricted to 5332, to avoid the fairly common muiderberg-type treatments. Of course it's possible someone plays multi 2♦ as a "six card weak two" and 2♠ as "five card weak two" or vice versa, and there's some weak two style out there where it shows 5-6 in the bid suit and 2-3 in every other suit and sort of intermediate values... but I'm willing to bet both of these are less frequent than people who just preempt aggressively (or not so aggressively).

Then again, I don't have a copy of bridge browser or a few million hands of data. I freely admit that this test is still "not perfect" but it seems a lot closer to accurate than the NT ranges.

I admit this is pretty good. However, there is still the problem that

• either partner doesn't know about/ignores this style, and therefore raises these weak twos too aggressively, or
  
• does take it into account, and will thus lose a bit when partner has a 6-card weak two.

I suppose most players fall into category a.

Arend

[cherdano]

How about this one:
Is it right to open in 4th seat with a full opening hand and spade shortness?

This has certainly minimal impact on the rest of the system. I am not sure whether the tendency to open such hands is uncorrelated to the strength of players, but I suppose this can be helped by using the rating feature of BridgeBrowser.

I suggest to restrict the search to something like 1=4 in the majors and exactly 13 hcp.

Arend

[inquiry]

cherdano, on Apr 14 2006, 07:50 AM, said:

How about this one:
Is it right to open in 4th seat with a full opening hand and spade shortness?

This has certainly minimal impact on the rest of the system. I am not sure whether the tendency to open such hands is uncorrelated to the strength of players, but I suppose this can be helped by using the rating feature of BridgeBrowser.

I suggest to restrict the search to something like 1=4 in the majors and exactly 13 hcp.

Arend

The Fourth seat open/no open is an easy one to program in.

For this test, on bid Shape/HCP I assigned first, second, and third seat with 5 to 12 hcp, fourth seat with 12 to 13 hcp and third seat with 0 to 1 spade (upto and including singleton spade Ace). Clearly this will include hands even with 8 or 9 card suits, so further restrictions might should be applied (like no longer than a five card suit or six card suit, and not something like 5-5 or 6-6).

On the bidding tab, I made the bidding specify exact seats, and forced first three seats to "pass". Fourth seat could bid anything it wants, including pass.

This search turend up 27,202 hands out of 23.5 million in the database I searched that meet all the requirements (passed to the fourth seat, and fouth seat had exactly 12 or 13 hcp and 0 or 1 spade).

Of these, 27K hands, 2161 people passed in 4th seat (not enough pearson points). The results for these hands was an average of MINUS 1.15 imps for the hand passing it out (1297 times), and an average of 39.18% matchpoints. This suggest passing an opening hand is the fourth seat IS NOT a winning bid, but may be influenced by shapely hands with other compensating factors (give you something to add to the search and try again).

As can be expected, if passing the hands out was BAD, then bidding was good. Opening 1C (+0.07, 50.7), 1D (0.08 and 51.52), and 1H (0.19 and 50.93) were marginally better than "average". 18 brave souls opened 1NT despite the singleton Spade and low point total this worked well at imps and poorly at matchpoints, but too few hands to worry about. Ppening bids of 2C (.98 and 50.44) and 2D (0.09 and 49.44) did well enough but opening 2H was less sucessful (at least at imps) wiht MINUS 0.61 but 52% mp. Most of the three and four level bids turned out very poorly for the fourth seat, the notable exception was 4H opening bid which was +2.16 imps and 55.21% MP, and opening 5C and 5D which both were 3+ imps, and but 5C did poorly at mp (45%) while 5D did well (59%). There were a lot of 4H opening bids but extremely few 5m, especially at matchpoints.

But this data, seems to suggest that passing an opening hand in fourth seat is not a good thing. After all, Bridge is a bidders game. Of course, if your partner opens extremely lightly in 2nd seat, that might in general favor an initial pass


One could subdived the results, easy enough. For instance, for 1♣ opening bids in fourth seat, it is easy to see (using the plot feature) how opening 1♣ with 12 hcp scored versus opening it with 13 (or opening with a singleton versus a void).

Turns out, opening on 12 hcp did slighly worse at imps, and slightly better at mp than opeing 1C with 13 hcp. With 1shcp. the imp average was 0.00, the mp average 51.16. While opening with 13 hcp averaged +0.12 but only 50.38%.

One might want to speculate as to why opening with minimum hands and short spades works so well in 4th seat (if this data holds up). I think the answer might be that if your RHO passes these days in third seat, he tends to be really broke as third seat light opening bids are all the rage. Thus, of the three other players at the table, the one statistically with most likely fewest hcp in RHO (assuming he will open most 11 hcp and many 9 and 10 hcp with an "excuse").

Ben