[helene_t]

Double dummy analysis, if I understand it correctly, means that you should pass out whenever PAR is negative?

In practice the expected score can be negative even if expected par is positive. This is because opps have more freedom in the bidding than you have since they are both passed hand. You are sometimes handicapped by not being able to show your shape without overstating your values. And sometimes partner will make a limit bid with his 11 count and you will be too high even if your PAR is positive.

So I think you should be a bid more conservative than DD simulations suggest.

This is probably less of an issue with balanced hands than with unbalanced ones.

[lexlogan]

I recall some time ago in these forums someone cited a study that showed it was better to open a 10-point hand with zero spades (a Goren 13 count) in fourth seat than a 10 point 5332 hand with 5 spades (Goren 11 count.) The Goren count was a better guide than the Rule of 15; counting a spade as a point was simply wrong. Unfortunately I can't get BBO's search engine to cooperate to find that discussion but I've completely given up following any rule in fourth seat except: would I open this hand in first seat?

[BillPatch]

mike777
maximum passes for Jack versus the J2 432 AQT32 KQ2 fourth hand opener.
Q4 AJ76 KJ94 T65 1ST SEAT
AT7 KJ65 974 K87 3RD
K43 AQT98 J5 J95 2ND
QT98 JT KJ75 A94 2ND
AK763 K86 9 8763 1ST
KQ875 J98 9 A875 1ST
A943 AT6 K654 54 2ND
In summarry I believe that Jack will open on any hand with 12 HCP including a K.

[BillPatch]

kgr
Your statements about my research are accurate except for your final conclusion. The hands that you provide in your OP were that were superior in overall strength to the average strenght of 12 hcp hands; they each contain 2 1/2 quick tricks. Only about 15% of 12 hcp bridge contain 2 1/2 or 3 QT. A wide majority of the weaker 12 hcp with doublton spades will provide negative returns at both MPs and IMPS if opened in 4th hand. Normally, the rule of 15 works well with most borderline hands. Thus, your intial hypothesis that reopening in general on any 12 hcp hand with a doubleton spade is false, while my study of the example hands you provided show that the subset of 12 hcp hands with a doubleton spade with 2 1/2 QT should be reopened.

Edit: My estimate of QT for 12 hcp hands was much too low. 53 1/3% new estimate. 1133est,3/13/ 2014

[kgr]

BillPatch, on 2014-March-13, 10:56, said:

kgr
Your statements about my research are accurate except for your final conclusion. The hands that you provide in your OP were hands that were superior in overall strength to the average strenght of 12 hcp hands; they each contain 2 1/2 quick tricks. Only about 15% of 12 hcp bridge contain 2 1/2 or 3 QT. A wide majority of the weaker 12 hcp with doublton spades will provide negative returns at both MPs and IMPS if opened in 4th hand. Normally, the rule of 15 works well with most borderline hands. Thus, your intial hypothesis that reopening in general on any 12 hcp hand with a doubleton spade is false, while my study of the example hands you provided show that the subset of 12 hcp hands with a doubleton spade with 2 1/2 QT should be reopened.

Ok, thanks. Makes sense

[BillPatch]

When I said that my study used double dummy anlysis I meant that the last 51 cards were played using Jack's double dummy analyser, not the analysis of absolute par. During the record of play we recorded absolute par for the last 80% of the hands, so I will comment on the differences in score. Jack bid to the suit and contract level(partscore, game, slam)over 50% and 90% of the time the side with the absolute par had a plus score.

Richard Pavlichek's website has an extensive comparision of results from actual play versus double dummy analysis for ach contract played in top competition. At he part score level declarer underperforms in actual play by .1 of a trick. Since in this analysi the openerer's side played about 60% of the time to the defender's 40 % to create a bias as suggested by Helenne of 2 tricks per 100 hands.

[BillPatch]

Sorry EGR, I made a major misestimate of the amount of 2 1/2 and 3 QT hands. A sample of 150 13 card
hands reveals that for every 100 12 hcp hands 14 2/3 have less than 2 QT; 32, 2 QT; 38 2/3, 2 and 1/2 QT
and 14 2/3, 3 QT. Thus, it appears that on about half of balanced hands with 12 points and a doubleton
can make positive results, even though they fail the rule of 15.

[mike777]

BillPatch, on 2014-March-13, 07:36, said:

mike777
maximum passes for Jack versus the J2 432 AQT32 KQ2 fourth hand opener.
Q4 AJ76 KJ94 T65 1ST SEAT
AT7 KJ65 974 K87 3RD
K43 AQT98 J5 J95 2ND
QT98 JT KJ75 A94 2ND
AK763 K86 9 8763 1ST
KQ875 J98 9 A875 1ST
A943 AT6 K654 54 2ND
In summarry I believe that Jack will open on any hand with 12 HCP including a K.

thanks ya this is a bias in the results. If pard cannot hold any of these hands that may change the overall results I would open all of these and even hands with less hcp and more shape in seats 1, 2,3.

That makes me even more likely to follow the rule of 15 in 4th seat.

to put all of this in context the lighter you open the more you will pass in 4thseat, the sounder you open then the lighter you can open in 4th seat.