Scouting Report?

[helene_t]

I'm not sure that this isn't significant, because on the majority of "slam vs non-slam" deals it's not random whether you bid slam or not. If (and it's a big if) one pair have worse judgement in the slam zone, then they will bid the wrong ones: this total swing you expect it not random, it's a reflection on their bidding ability.

But this non-randomness is an alternative hypothesis. Of course, there are lots of alternative hypotheses that can't be rejected. But Arend's point is that the zero hypothesis, namely that a slam swing is equaly likely to go one side or the other, can't be rejected.

 

The slam swings are "random" in the sense that if 50% of all (in the long run) slam swings go this way and 50% go the other way, then the number of slam swings in the 40-sample that go this way is (40,0.5) binomial distribution, i.e. one slam swing is independent of another. This will normally be true unless playing goulash. (It could also be violated if the team who's lacking behind is going for swings, but that would make the dispertion higher and thus make the findings even less significant).

[hotShot]

Values that could be of interest:

 

% of bid contracts made

% of doubled contracts made

 

% of doubled opps but they made

 

big numbers here might show "solid bidding style"

 

declarer play:

% of the possible tricks made in bid contracts with reference to the double dummy result for the bid contract.

Example:

You play 2♥, dd solver says you can make 9 tricks and you got only 8 or perhaps you got 10.

 

defense:

% of possible defense tricks taken compared with dd solver result.

Example:

Opps play 2♥, dd solver says you can make 5 tricks and you got only 4 or perhaps you got 6.

 

sacrifices over opps game/slam:

Opps bid game/slam and your side played:

% of sac's that made a good score

 

If you opps have a low number here you should X them more often.

[cherdano]

I'm not sure that this isn't significant, because on the majority of "slam vs non-slam" deals it's not random whether you bid slam or not. If (and it's a big if) one pair have worse judgement in the slam zone, then they will bid the wrong ones: this total swing you expect it not random, it's a reflection on their bidding ability.

 

Let's say that

i) All potential slam hands are 100% or 60% each equally likely and each with nothing to the play.

ii) Pair A, who are too conservative, bid all the 100% slams, but not the 60% ones

iii) Pair B bid all of them

iv) The swing for slam off/game making or both making is 10 imps either way

 

In 40 potential slam deals under these conditions, you expect

20 flat boards (excluded from winkle's analysis)

12 10 imp swings to pair B

8 10 imp swings to pair A

 

or a total expected swing of only 1 imp per board

 

In fact, if you then add in the condition that F&N are more likely to make 12 tricks than their opponents on average, and more likely to take 2 tricks in defence on average, it makes things look even worse (particularly if they are over-aggressive rather than conservative in the bidding).

Various comments:

1. I am not a statistician, so I don't really know which confidence analysis would be most appropriate here. (If I wanted to do this carefully, I would use Baysian formula to compare the a-posteriori likelyhood of, say, "FN are as good slam bidders as their opps" with "FN expect to lose 1 IMP per board on slam bidding swings" assuming they have equal a-priori-likelyhoods.) However, I think generally the "physicist's approach" -- compute the standard deviation and claim it is significant if "result +- 2*std deviation" is above or below what the null hypothesis predicts -- works well enough.

2. Your example above would get a loss of 2 IMPs per board in winkle's computations, note 1.

3. Maybe we are playing a different game :) but I seem to see many slams that are pretty close to 50% (finesse plus or minus small chances).

4. I guess Helene has explained it better than me...

 

Arend

[Rain]

Duboin/Bocchi and Fantoni/Nunes are awful....in slam bidding decisions

 

 

:D

[MickyB]

I believe that your expected score when opening a strong club depends very much on your hand.

 

Minimum-ish balanced hands are happy to open 1♣ and then pass in competitive auctions. They rate to do well if partner describes his unbalanced hand.

 

Stronger balanced hands may have to take an uncomfortable call in competition, but a standard 2NT opening isn't dealing with these hands too well either.

 

Three-suiters are happy to pass if the opposition settle in one of their suits, and double for takeout if not.

 

Offensive single-suiters, particularly with a major, are well described by opening a strong club and then rebidding their suit at whatever level is necessary.

 

Of course, there are exceptions - maybe the auction will be at 5♦ by the time it gets back to you, and you will feel unable to introduce your massive club suit. Maybe the opponents will manage to play in your fit, giving you +350 against a slam, but those tactics can certainly backfire.

 

Other hands tend not to cope well in interference, as their second call won't describe the hand nearly so well.

 

Credit to DavidC - he covered these sorts of issues on his bridge blog much better than I could.

[hotShot]

I've been playing around and made me a program that is reading lin-files and analyzes the card play. At the end I calculate a number: unlucky played cards / board.

 

An unlucky played card is a card that reduces the number of tricks for your side.

This could be just unlucky as in not fishing a stiff K or some serious error.

 

A few results:

Star (world class) 0.22 (070 boards serious competition)

GIB 0.3 (about 1000 there are 3 GIB's playing each board :P )

Junior champion 1 0.33 (150 boards serious competition)

Junior champion 2 0.38 (200 boards training and serious competition)

Junior Star 0.4 (570 boards fun team games)

Senior Star 0.48 (330 boards fun games with other stars)

Me 0.5 (10000 boards with hundreds of pickup partner)

Intermediate 0.64 (700 boards)

Beginner Level 0.83

[Guest Jlall]

Junior Star 0.4 (570 boards fun team games)

hmmmmmmmm lol.

 

You need a sober/drunk filter as well :P