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Duplicate pairs match point anomaly

#21 User is offline   barmar 

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Posted 2013-March-11, 08:55

We've had this discussion many times before -- it seems like every player new to duplicate eventually notices this, and feels the need to bring it up.

Duplicate bridge is a game of objective scoring -- your results are simply based on the bridge score. It's not like figure skating or gymnastics, where there are judges watching you, deciding how well you played (there was a thread last year around the time of the Olympics, where someone opined that games with such scoring don't even deserve to to be called "sports").

It's based on this objective measure, and doesn't try to determine why you got a certain score. Sometimes it's because of how you bid and played/defended, other times it's totally due to the opponents. The expectation is that in the long run, the hands where the opponents fix you and give you gifts will cancel out, and your overall results will be due to your abilities. And this seems to ring true -- the same pairs tend to be at the top of the results in the club every week, and it can hardly be because their opponents regularly give them gifts. They must be doing something right most of the time.

#22 User is offline   billw55 

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Posted 2013-March-11, 11:16

To the OP, the answer is quite simple: you are right. This does happen in pairs competition, and is considered normal and expected. Everyone who has played much bridge has received many outlying scores, both tops and bottoms, that they did nothing to deserve. Over the long run, it evens out, more or less.

edit: to be clear, you are *not* right that going passive is a good strategy. In general, aggressive bidding pays off in pairs competitions.
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#23 User is offline   ArtK78 

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Posted 2013-March-11, 12:07

Many years ago, in the first regional event that I won, at unfavorable vul, one of my opponents decided to play 3 of a suit in which my partner and I could make a grand slam. My partner and I slipped a trick on defense and achieved only 2300. [By the way, as weird as this result seems, it was duplicated across the field twice.]

Was it unfair to all of the other pairs sitting in our direction (and, in a broader perspective, for all of the pairs condending with us for the win) that our opponents went for 2300 on this hand? Maybe so. But that is just the way it is.
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#24 User is offline   Free 

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Posted 2013-March-11, 15:07

View Postmdietz39, on 2013-March-09, 09:03, said:

I have a question about an anomaly in duplicate pairs match point scoring.

Assume Double Dummy indicates that a specific board allows N/S to reach 6 Hearts. This is also verified by Deep Finesse. We have 6 tables playing, nobody vulnerable.

N/S pair 1 bids and makes 6 Hearts
N/S pairs 2, 3, 4, 5 bid 4 Hearts and makes 6 Hearts
N/S pair 6 bids 3 Hearts and makes 6 Hearts
Assume that E/W have too few HCP to enter the bidding at all.
Also assume the leads, plays, tricks, rounds are identical on all 6 tables.

N/S pair 1 scores 980, pairs 2, 3, 4, 5 each score 480, and pair 6 scores 230. They respectively receive match points of 5, 2.5, 2.5, 2.5, 2.5, and 0.

E/W scoring will then be E/W pair 6 gets -230, pairs 5, 4, 3, 2 each score -480, and pair 1 scores -980. They respectively receive match points of 5, 2.5, 2.5, 2.5, 2.5, and 0

Notice that because N/S pair 6 bid incorrectly they received a bottom but E/W pair 6 gets the top board. Also N/S pair 1 bid correctly and received a to board while E/W pair 1 gets a bottom.

It appears that E/W pair 6 benefits greatly because of the mistake of N/S pair 6 even though E/W 6 did nothing different from any of the other E/W pairs. Remember the only difference in the round was the difference in bidding by N/S. At the same time E/W pair 1 is penalized greatly for having bid and played correctly.

It seems to me that the proper tactic in bidding is to not overcall, especially if it is obvious your opponents are going to get the auction. Do not try to raise them to a higher level but allow them to get the auction at the lowest possible level. That way when they score, your negative score will be less than the scores of those on your side of the table and thereby you will receive more match points.

Will somebody please explain this to me?

Thank you
Mike

Next board EW pair 6 makes a mistake and gets a bottom. As a result NS pair 6 gets a top. At the same time, pairs 2, 3, 4 and 5 reach the normal contract and all make the same amount of tricks. EW pair 1 gives an overtrick away and has another poor score. Result: the best pair wins, the worst pair loses, and the rest has an average. And now the system looks perfect...

Your score is calculated over several boards, not just one. "You win some, you lose some" is applicable here, because opps make mistakes against you (giving you good scores) and opps make good plays + you make mistakes (giving you bad scores). In the long run this evens out if you're an average player. When you're a better player you'll have a better average, but in a single session you can reach anything from 40% to 75%. The inverse is true for poor players.
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#25 User is online   awm 

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Posted 2013-March-11, 16:12

The same is true in sports as well. You can win a tennis point because you hit a great shot, but you can also win a point because your opponent made an unforced error, even a silly one. Or you can win a point on sheer luck when your shot hits the net and barely dribbles over.

Fortunately a tennis match has a lot of points and this stuff tends to even out and the better players tend to win. Serious bridge competitions are a lot of boards for the same reason.
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#26 User is offline   mycroft 

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Posted 2013-March-11, 18:19

And the game gets better as the game gets better too. It's yet another reason to play in the strongest fields you can; horrible luck from those "out of your control" hands is lessened, and good luck from them is increased.

There was a hand this weekend; 13 tops, but the hearts were AJx opposite a singleton, and the suit was clubs. Not the trickiest grand in the world to find, but not the easiest, either.

In the side game, there was a 1520, a 1020 and a 1440.
In the B game, +940 was worth 3/8; one pair only bid a grand (and it was NT). The rest bid 6NT.
In the A game, +940 was worth 0.5/8; and even 7 got you a below-average score.

Pity the pair in the B game whose opponents can bid well enough to find 7. The pairs in the A game who couldn't deserved what they got. The opponents of the ones that could could take comfort that they were going to get a reasonable score - but do the opponents of the ones that couldn't "deserve" their top?
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#27 User is offline   Fluffy 

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Posted 2013-March-14, 08:25

this is why Pair contests are normally scored in MPs and not in IMPs
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#28 User is offline   jdeegan 

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Posted 2013-March-14, 10:46

:D Life is not fair. This is why you are a LOSER.
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