Duplicate pairs match point anomaly

[mdietz39]

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

[ArtK78]

Don't try to draw too many conclusions from the results on one hand.

 

Trying to draw any conclusions about EW tactics on this hand is absolutely pointless. EW was at the mercy of NS on this hand. The EW results were purely random, as it was entirely a function of what NS did. As you stated, the EW that scored a top did exactly the same things that the EW that scored the bottom did, as well as all of the others who scored average. What are you supposed to conclude from that?

 

Now, if you said that EW pair 6 did something that caused NS pair 6 to misevaluate their cards, or that EW pair 1 did something to propel their opponents to slam, there might be something to be drawn from this example.

[awm]

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.

 

The first paragraph is absolutely true. Sometimes your score on a board has more to do with what the opponents did right (or wrong) than anything you did. This is true at IMP scoring as well of course. However, there is no particularly easy way to rectify this, except to notice that you are playing many different opponents (in a good movement and a small field, perhaps every other opponent) and that in the long run this should tend to average out.

 

The second paragraph does not follow at all from the first paragraph. There are many reasons to bid such as:

 

(1) If I take up a lot of space, it becomes harder for opponents to negotiate the best contract; in particular determining whether they have slam can become quite difficult. On this hand, if I pass maybe the auction starts 1♣-1♥-2NT-3♥ followed by some cuebids and a 4NT blackwood bid and eventually 6♥. If I preempt 4♠ the auction may go 1♣-4♠-Pass-Pass-Dbl-Pass-5♥-All pass (for example) because their cuebids and blackwood are taken away and they can no longer figure out that they have a "perfect fit."

 

(2) If I take up a lot of space, maybe opponents stop in the wrong strain altogether. For example it might go 1♣-4♠-Pass-Pass-Dbl-All pass which might be better than defending 6♥. Or it might go 1♣-1♠-Dbl-3♠-3NT-All pass and this might be better for us than defending 4♥.

 

(3) I might get a better lead from partner on some hands; here if the auction goes 1♣-1♠-2♥-Pass-4♥-All pass partner has an easy spade lead, whereas after the original auction of 1♣-Pass-1♥-Pass-2NT-Pass-3♥-Pass-4♥-All pass partner could easily lead a diamond or even a club or a trump. Of course on this hand it seems the lead doesn't matter even for holding down the overtricks, but that will often not be the case.

 

(4) I might push the opponents into something not making on some hands (evidently not this one).

 

And all these are ignoring the possibility that it really is "our hand" which I usually won't know at my first chance to bid!

[PhilKing]

It's not an anomaly - it's just part of the game ("In order for us to do well, it is necessary for our opponent's to do badly.") There are four players at the table, and the cards are rarely evenly divided, so we are not always the masters of our own destiny. And bridge is a game of imperfect information, so the best play is not always rewarded.

 

If you don't like it, play teams, where at least your teammates have the chance to bid slam. Alternatively, you can take up chess, where virtue is always rewarded.

 

And if you want Deep Finesse to give you a free pass every time you get a bottom, forget it. Sometimes they make slam because you made it easy for them in the bidding or made it obvious for them to find the winning line, and Deep Finesse is no King Solomon when it comes to matters of judgment.

[Stephen Tu]

It's hardly an anomaly; it happens all the time at pairs! As Art says, the results for E/W on this one board are essentially random, it's whether or not you face the good or bad opps on this board. A certain # of boards per session are simply not under your control. You either get gifted a top (opps do something ridiculous despite no pressure from you), or "fixed" with a bottom (opps do something unusually clever not duplicated by the field, or something ridiculous that works on a lucky lie of the cards).

 

There's nothing one can do about this. But the more boards in the tournament, or the more tournaments one plays, the effect of these random boards trends towards no effect. What you are left with is the stuff that *is* under your control. But any single session could easily be +/- 6 percent or more from an unusual # of gifts unbalanced with fixes.

 

Your "don't overcall" theory also doesn't usually work, except occasionally against the worst chronic underbidders. It's only valid when your active bidding pushes the opponents into a *making* game or slam that they would not have bid uncontested. Most pairs bid more accurately without competition, so they aren't going to be missing many good games/slams if you aren't disturbing their auctions. If they have game they are supposed to be getting there whether you are passing or bidding. If you are letting them play a cozy 2H/2S all the time on their partial deals, you are going to get crushed relative to the pairs who are getting in there, and forcing them to bid & make 3h/3s (here if they score 140, you haven't made it any worse than if you let them make 140 at the 2 level, but if you set them you have achieved a huge victory), or defend accurately vs. your contract (and maybe they have to also double you in order to get a good score, and nv they might have to set you two!). Getting in the bidding when you are supposed to usually generates more mistakes from the opponents, not fewer, because you rob bidding space that could have been utilized to make more accurate decisions. Just look at how many posts on these forums are about competitive auctions, what bid to choose, it's often not clear!

[Siegmund]

It appears that E/W pair 6 benefits greatly because of the mistake of N/S pair 6

 

 

The only way any pair ever beats par -- which was -980, for EW on this board -- is by taking advantage of a mistake by an opponent.

 

More generally, only 25% of your score is determined by your own actions. Another 25% each from your table opponents, all of the other pairs sitting your way, and all of the other pairs sitting the opposite way. That is true of all duplicate bridge formats. The theory is that, by comparing with a large enough number of tables, the last two categories will average out to something close to par.

 

As the others have said, none of that changes the fact that you need to bid and play in whatever way maximizes your chance of avoiding a mistake and your opponent's chance of making a mistake. Overcalls can allow your side to outbid the opponents, either making or as a sacrifice, help your partner defend better, or deprive the opponents of bidding spade they need to find their best spot. (And, yes, on a bad day, overcalls will tell declarer how to play the hand. Every time you do something that conveys information about your hand, you are betting the information is more useful to your partner than to your opponents.)

[GreenMan]

FWIW this is the foundation of the concept of "field protection": In a strong field, most NS pairs will be in 6H if it's reasonably biddable, so the EW pairs who score -980 will get scores much closer to average. Similarly, if you bid a good game or slam that fails on a bad trump break or an early ruff, then you should have plenty of company and not have to worry about the timid pairs stopping below game.

 

If the slam on the original hand here was just a lucky shot that most pairs wouldn't reach, then you're truly fixed, BUT most of the time against this pair you'll benefit from their wild bidding, so it'll work out in the long run. Just not today. :)

[mdietz39]

Don't try to draw too many conclusions from the results on one hand.

 

Trying to draw any conclusions about EW tactics on this hand is absolutely pointless. EW was at the mercy of NS on this hand. The EW results were purely random, as it was entirely a function of what NS did. As you stated, the EW that scored a top did exactly the same things that the EW that scored the bottom did, as well as all of the others who scored average. What are you supposed to conclude from that?

 

Now, if you said that EW pair 6 did something that caused NS pair 6 to misevaluate their cards, or that EW pair 1 did something to propel their opponents to slam, there might be something to be drawn from this example.

Except I took this example from our local club pairs game of a couple of weeks ago. We were one of the middle N/S pairs so it did not affect us. However I took the results of the games and removed this one board. It changed the master points allotments because it removed E/W pair top board which allowed another pair of E/W to get points.

 

And it was not an isolated situation. In the 24 boards there was this one and seven other boards with the same type of anomaly except those seven did not involve a slam, only partial and game scores.

 

In fact the example I used was not quite the way I said in my earlier message. The N/S pair did not bid 3 and make 6, they bid a minor and made 2. DD and Deep Finesse both state only 1 Club is available. Since they scored 90 I do not know if they bid 1 and made 2 or bid and make 2. If it was the first case then not only did N/S bid incorrectly but E/W also defended badly. And yet they got the top board.

 

Mike

[helene_t]

It is probably not good to award masterpoints on the basis of 24 boards. In the Netherlands they require 100 boards for awarding masterpoints and then the chance that a mediocre pair gets enough gifts from the opponents to earn masterpoints is smaller.

[PhilKing]

It is probably not good to award masterpoints on the basis of 24 boards. In the Netherlands they require 100 boards for awarding masterpoints and then the chance that a mediocre pair gets enough gifts from the opponents to earn masterpoints is smaller.

 

But then how is the mediocre player supposed to get masterpoints? :(

 

It would be even worse if they were punished for not living up to Deep Finesse though .....

[wyman]

It is probably not good to award masterpoints on the basis of 24 boards.

 

This depends on your motivation for awarding masterpoints.

[Vampyr]

It is probably not good to award masterpoints on the basis of 24 boards. In the Netherlands they require 100 boards for awarding masterpoints and then the chance that a mediocre pair gets enough gifts from the opponents to earn masterpoints is smaller.

 

How long is a session in the Netherlands?

[GreenMan]

Except I took this example from our local club pairs game of a couple of weeks ago. We were one of the middle N/S pairs so it did not affect us. However I took the results of the games and removed this one board. It changed the master points allotments because it removed E/W pair top board which allowed another pair of E/W to get points.

 

It sounds as if you are complaining that if someone gets a poor result on a board it hurts their chances of winning the event. I am not sure why this should be controversial.

[Vampyr]

And it was not an isolated situation. In the 24 boards there was this one and seven other boards with the same type of anomaly except those seven did not involve a slam, only partial and game scores.

 

In any duplicate session there will be a number of crucial boards -- those where the top and/or bottom scores are minimally (or not at all) shared, and a pair will get all or none of the matchpoints available (or nearly all or none). On these boards you would like to be the side with more cards, so that you have some control over your destiny. This is a large part of the luck element of the pairs game, and if you find this a big detriment to your enjoyment of the game, it will be best, as another poster mentioned, to play more teams.

 

Think about joining a local league, playing for your club or county (there are often B and C teams, so if you are not one of the top players you may still get the opportunity).

[mdietz39]

It sounds as if you are complaining that if someone gets a poor result on a board it hurts their chances of winning the event. I am not sure why this should be controversial.

I am wondering why the opponents of someone who gets a poor result should get the top award. Team A E/W gets 0 match points because they scored only 90 when 980 was possible. But because team A N/S has a score of -90 they get top board while the other N/S pairs with scores of -980 get bottom board. Does not seem fair to me.

Mike

[PhilKing]

My eyes are bleeding.

[awm]

I am wondering why the opponents of someone who gets a poor result should get the top award. Team A E/W gets 0 match points because they scored only 90 when 980 was possible. But because team A N/S has a score of -90 they get top board while the other N/S pairs with scores of -980 get bottom board. Does not seem fair to me.

Mike

 

How do you suggest we distinguish "they got a bad score because they messed up" from "they got a bad score because we did something good"? Just because they declared the final contract doesn't mean we had no decisions -- our bidding effects what the contract will be and our defense effects how many tricks they make! Since there is no objective way to tell on the vast majority of boards, it his much simpler to just score on the basis of the final result and realize this sort of "luck" will even out over time.

[EricK]

Except I took this example from our local club pairs game of a couple of weeks ago. We were one of the middle N/S pairs so it did not affect us. However I took the results of the games and removed this one board. It changed the master points allotments because it removed E/W pair top board which allowed another pair of E/W to get points.

 

And it was not an isolated situation. In the 24 boards there was this one and seven other boards with the same type of anomaly except those seven did not involve a slam, only partial and game scores.

 

In fact the example I used was not quite the way I said in my earlier message. The N/S pair did not bid 3 and make 6, they bid a minor and made 2. DD and Deep Finesse both state only 1 Club is available. Since they scored 90 I do not know if they bid 1 and made 2 or bid and make 2. If it was the first case then not only did N/S bid incorrectly but E/W also defended badly. And yet they got the top board.

 

Mike

Presumably these 8 "anomalous boards" rewarded different pairs - you win some, you lose some. But over a long session your skill (or lack of it) will tell.

[Vampyr]

I am wondering why the opponents of someone who gets a poor result should get the top award.

 

Do you have another idea about how to score a pairs event?

[GreenMan]

I am wondering why the opponents of someone who gets a poor result should get the top award.

 

Um, because they got the best score? It's a radical notion, I know.

 

You're focusing on the INDIVIDUAL BOARD as the unit of measure for fairness. The point of playing more than one board in a session is to even out the effects of chance that you don't like. So unless you're arguing that the system AS A WHOLE is unfair to certain pairs, then I don't see what the problem is.

[barmar]

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.

[billw55]

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.

[ArtK78]

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.

[Free]

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.

[awm]

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.