[Siegmund]

Had a funny thing happen yesterday.

My non-bridge-playing girlfriend was in the mood to ask me a bunch of questions about how tournaments (and rubber bridge games) are scored, and at some point I grabbed the nearest hand record from a recent sectional, and my convention card, and I talked her through a few of the hands: "On board 1, you see my side has all the hearts, and the analysis box says -450 for hearts making 5 is par... when I actually played it, my opponents misjudged to bid 5C, and we doubled them and got -500... and got 19 matchpoints out of 20." (Yes, a 21-table pairs game with a web movement.)

We got off on a tangent about whether people were scored by comparing their results to double-dummy par rather than to the results at other tables .... I pointed out a couple other hands where reasonable bidding never reached the par result (e.g. a 1NT-3NT hand where the other side has a lucky paying sacrifice in a 4-4 club fit) ... then looked for a simple hand where most people achieved double dummy par to see how close to average I scored on it.

Twenty-six boards, and not a single one where the result at my table was the double-dummy par score. Yes, it was a night when I had had a big game and ruined it with four disasters in the last six boards ... but wow. If you had asked me two days ago, I would have guessed that in a typical session, double-dummy par is achieved at the table six or eight times.

[Lord Molyb]

Quote

If you had asked me two days ago, I would have guessed that in a typical session, double-dummy par is achieved at the table six or eight times.

I agreed with this, but then I looked through a random game I played back in August and there was only one par result in 24 hands.

A lot of the variants were someone messing up the bidding (not finding game/slam) or finding the wrong lead.

[mikeh]

Siegmund, on 2014-November-03, 22:47, said:

We got off on a tangent about whether people were scored by comparing their results to double-dummy par rather than to the results at other tables .... I pointed out a couple other hands where reasonable bidding never reached the par result (e.g. a 1NT-3NT hand where the other side has a lucky paying sacrifice in a 4-4 club fit) ... then looked for a simple hand where most people achieved double dummy par to see how close to average I scored on it.

Twenty-six boards, and not a single one where the result at my table was the double-dummy par score. Yes, it was a night when I had had a big game and ruined it with four disasters in the last six boards ... but wow. If you had asked me two days ago, I would have guessed that in a typical session, double-dummy par is achieved at the table six or eight times.

I assume you are looking at the hands truly double-dummy, which means best defence and playing for the actual lie of the cards rather than playing correctly, single dummy.

I used to give a talk at a local club where I would address hands from the previous week, and the club provided printouts that used double-dummy software to say how many tricks each side could take in the various denominations, and most of the (not very good) players would frequently argue that if the sheet said E-W could make, say, 9 tricks in spades, then they ought to be making 9 tricks in spades.

It got boring, fast, explaining week after week that double dummy analysis was an extremely poor way to learn how to play the cards.

Double-dummy bridge bears less relationship to real bridge than do platonic solids to real objects.

[KurtGodel]

I feel it depends on the standard of the event a little bit. If you play in a club duplicate I feel that you rarely get double dummy results, but in tournaments I feel it's a lot closer. I think on Richard Pavlicek's website there was some analysis about how many tricks were taken vs. double dummy in high-level tournaments and the results were extremely close.

[Cthulhu D]

KurtGodel, on 2014-November-05, 07:00, said:

I feel it depends on the standard of the event a little bit. If you play in a club duplicate I feel that you rarely get double dummy results, but in tournaments I feel it's a lot closer. I think on Richard Pavlicek's website there was some analysis about how many tricks were taken vs. double dummy in high-level tournaments and the results were extremely close.

It gets very good after the opening lead. It turns out that the opening lead is often the swingest decision. I think it's likely because while the first decision (the lead) is made off 13 visible cards cards + the bidding, once the lead has been made the responder knows about 27 cards, plus the bidding and plus whatever agreements the opening lead is made with. It's likely that at that point the defenders can locate something like 30 cards in the deck fairly precisely, and probably another ~9 on the majority of hands.

Given expert defence, they'll know a lot more after the lead.