[oryctolagi]

A very general question, this.

Received wisdom tells us, playing any form of duplicate becomes a true test of skill, because the 'luck of the deal' inherent in Rubber and Chicago, is eliminated. I had no experience of duplicate before joining BBO, but over the months I've got used to the system. Mostly playing IMPs pairs, I've come to believe that it's a pretty good way of assessing one's ability.

But is this always the case?

I'm not complaining about the result I got today, but sympathising with my opponents. My partner and I played a 7NT, laydown, and got nearly +14 IMPs for our pains. This was largely due to the fact that we were one of only two tables out of the 16, to reach a grand, so I suppose we deserve some credit for the bidding.

But what about our poor opponents? They landed a -14 score through no fault of theirs, I feel. At no table did NS fail to take 13 tricks (it wasn't a very interesting deal, after all). Also, at no table did EW take part in the bidding - except at one table where a double cropped up at one point. So they had no chance to swing anything in their favour.

This is not the first time I've had the feeling that there's still plenty of an element of chance in IMPs pairs. Perhaps in all duplicate systems.

[Zelandakh]

No, there is sometimes a great deal of luck involved. If you get easy flat boards against weak opponents and wild swingy boards against the best, it will usually work out worse than the other way around. On BBO, scoring a "normal" game tends to receive several IMPs and a "normal" slam gets a considerable reward. In the long run these will tend to even out but in any given session you can easily end up +20 or more in a few boards without having played particularly well.

[perko90]

I guess it's about as fair as it can be. But there's still an element of luck.
There will always be cases like the one you describe above. Or the slam that comes down to a pure finesse - making you either look like a genius or a dud, depending on which way the finesse goes. Sometimes poor bidding/play gets rewarded - a shaky overcall catches partner w/ a great dummy. Even forgetting conventions can be an unexpected boon. Imagine having the opponents open 2♦ and alerted as Flannery (5-4 H&S w/ an opening hand). But your side misses a cold 4♥ because the opener forgot they agreed to Flannery and instead had a weak 2 bid w/ just diamonds. There's no adjustment either because the alerter gave proper info according to their agreements.
All you can do is take comfort in knowing that there's plenty of room for skill to win the day. And in the long run, playing the percentages will win out. But on any given day, luck can be with or against you. And sometimes there's comfort there, too. Having a bad round can't ALL be your fault, right?

[gwnn]

Nope. Next question please.

[barmar]

No, it's not necessarily fair. The scoring method is not able to tell which side caused a particular result. So you can get a good score when you do something well or when your opponents make a mistake, and conversely your bad score can be because you made a mistake or your opponents were good.

And you can also just be lucky. If you bid a 10% slam (not counting sacrifices), it's probably due to a mistake in the auction, so theoretically you should be punished with a bad score. But if the cards all happen to be placed such that it makes, you'll instead get a great score (since it's unlikely that other pairs will have screwed up the auction similarly).

[awm]

There are basically three elements of luck in bridge:

1. Which pair has the better cards? If you have the good hands, you are more likely to get a big positive score whereas if you have lousy hands you're probably settling for a minus.
2. Where are the cards located? For example, you bid a game where you need a particular opponent to hold a king in order to make it. This is different from #1 because it's not about which pair has the card, it's which member of the pair has the card (or what the distributions happen to be, etc).
3. Which opponents do you face? Some hands are particularly suited to some style or bidding system, such that you will do a lot worse facing particular people on these hands. Also, some hands offer great opportunities for skilled opponents to take advantage through better bidding or play, whereas other hands are more "boring."

Duplicate scoring removes luck element #1. There are still luck elements #2 and #3. All of these luck elements tend to even out over the very long term, but the more luck elements you have the longer it will take to even out and the more likely it is that a weaker pair will win over a stronger one.

[Vampyr]

awm, on 2016-January-16, 18:36, said:

There are basically three elements of luck in bridge:

1. Which pair has the better cards? If you have the good hands, you are more likely to get a big positive score whereas if you have lousy hands you're probably settling for a minus.
2. Where are the cards located? For example, you bid a game where you need a particular opponent to hold a king in order to make it. This is different from #1 because it's not about which pair has the card, it's which member of the pair has the card (or what the distributions happen to be, etc).
3. Which opponents do you face? Some hands are particularly suited to some style or bidding system, such that you will do a lot worse facing particular people on these hands. Also, some hands offer great opportunities for skilled opponents to take advantage through better bidding or play, whereas other hands are more "boring."

Duplicate scoring removes luck element #1. There are still luck elements #2 and #3. All of these luck elements tend to even out over the very long term, but the more luck elements you have the longer it will take to even out and the more likely it is that a weaker pair will win over a stronger one.

#1 is not entirely removed by duplicate scoring, at least if you are talking about matchpoints. If you do not hold the cards your fate will not be in your own hands, and this will randomise your scores. Also the hands you arrow-switch on is a randomising factor. I guess "random" evens out over the long term.

Your #2, on the other hand, is entirely removed by duplicate scoring.

[awm]

It is sad that people think they have no control over the result when they do not hold good cards. In fact you can often get an excellent score by defending well, especially at matchpoint scoring. Of course this excellent score might be -420 (when everyone else is -450) and of course that will not pay at non-duplicate scoring (big minus) nor is it really useful at IMPs. In any case, the type of "luck" where my opponents did something good that no one else did falls into category #3 (who you played) and not #1 (who had the cards).

As for #2, it is true that if the whole field is in the same contract, it may be a push result. But if I am one of the few to bid a game which is odds-on to make, and it goes down because of where opponents cards are located, I will end up with a bad but "unlucky" result.

In any case, it's important to remember that "fair" and "totally free of luck" are not the same thing. In fact even chess has luck involved (generally in the "who you play" sense). Most sports have luck (in that outcomes can be decided by inches where no one has the level of accuracy needed to really control that outcome). Nonetheless the games are "fair" and the better players win a lot more often than the weaker ones when they face each other head to head.

[ahydra]

This is the main reason why I prefer teams to pairs. At teams (at least) one of you is guaranteed to have the critical decision to make on any hand, so the odds of getting a bad score purely due to opponents' decisions (bidding the slam, or being the only pair in the room to find the slightly offbeat but as-it-happens successful opening lead, etc) is much reduced.

Of course, it's still possible to lose by bad luck at teams due to things like system and style differences (or opponents bidding 5C on a 5-1 fit and making it due to a freaky distribution </rage>).

ahydra

[Zelandakh]

awm, on 2016-January-16, 18:36, said:

There are basically three elements of luck in bridge:

Surely whether the hands that come up are good for your own system is also a luck factor.

[jerdonald]

BBO forum,
Many good points have been made on this subject and it's true that
duplicate isn't and can't ever be completely fair. Sometimes it's
just "the luck of the draw" as to which table you at when you play
which boards.

I've always thought that "eight is enough" is about as fair as it
can get because your team gets both north/south and east/west and
there is by definition some control of the overall strength of the
teams.

Jerry D.

[Vampyr]

awm, on 2016-January-17, 03:09, said:

It is sad that people think they have no control over the result when they do not hold good cards. In fact you can often get an excellent score by defending well, especially at matchpoint scoring.

No, it's not so much that. Bidding and making a game when the number of tricks is straightforward, is usually, in a mixed field, above average. When the opponents are holding the cards, you will generally do poorly when they reach the right contracts-- and stay out of the wrong ones.

In sessions where one line has considerably more values than the other, the players in the former line will have results that are more true-to-form, and the strongest pairs in that line will be more likely to win (provided they are more or less as strong as the better pairs in the other line). This is assuming a one-winner movement, of course. But even in a two-winner movement, the line with the cards will be much more likely to have results in descending order of skill.

This is very evident in Swiss pairs.

[tm255]

I'm glad to see this thread. I'm new to duplicate, and have been told repeatedly at the local club that things are "always even" and there is "no luck involved." That never made sense to me, especially in small sessions with only a few tables and limited number of hands.

[mikestar13]

What they well-meaning "there's no luck in duplicate bridge" crowd (do they say it in the same tone as "there's no crying in baseball"?) are trying to say is that duplicate bridge is a truer test of skill than rubber/Chicago bridge because there is significantly less luck involved--not that there isn't a fair amount of luck involved. This statement is true, but not as catchy as the untrue statement they are making. On a related note some of these same persons dismiss non-duplicate forms of bridge as being mostly or all luck, a statement that is also untrue. Back in the days, I made a significant contribution to paying my rent by playing Chicago bridge for money, though I had some spectacular losing sessions along the way. I doubt I could have done that tossing coins or buying lottery tickets....