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WBF VP scale changes Huzzah!

#21 User is offline   Fluffy 

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Posted 2012-December-22, 11:02

Since this has been resurrected I will throw a random idea.

IMO a team that wins 13-2 IMPs should score better than a team that wins 113-102, not by much but by some ammount nevertheless. giving 95% VPs to IMP difference and 5% to IMP ratio could be more accurate to me.
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#22 User is offline   pigpenz 

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Posted 2012-December-23, 11:28

 Rossoneri, on 2012-December-21, 20:49, said:

Using U-25 players as guinea pigs of course, what other useful purpose do they serve? :P

J Lall probably came up with it when he turned 25
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#23 User is offline   mycroft 

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Posted 2012-December-24, 12:27

 Fluffy, on 2012-December-22, 11:02, said:

Since this has been resurrected I will throw a random idea.

IMO a team that wins 13-2 IMPs should score better than a team that wins 113-102, not by much but by some amount nevertheless. giving 95% VPs to IMP difference and 5% to IMP ratio could be more accurate to me.
Not sure I agree with this. I certainly don't in the ACBL, where almost never are people playing the same boards. Yes, VPs are badly biased based on "swinginess", too, but adding a penalty to the swing set is even more random.

But in the real world, where everybody's playing the same hands, that does tend to disfavour the "oddball system" players. I play K/S in a "2/1, strong NT" world. As a result, we "wrongside" 80% of the contracts where opener has a balanced 12-17. We win some, we lose some, we draw (+/- an overtrick) a lot. But we're going to be punished for playing a system that will, on average, score about 5IMPs more a 7-board set than playing "standard" - if we win. If we lose, the opponents will be punished.

Precision does similarly. Anybody playing a highly aggressive preempting style, or a 10-12 NT, or T-Walsh in a "standard" world has the same problem. We play it because it's better, or suits us better, or is deliberately high-variance in a world where we'll probably lose if we don't roll the dice; but now high-variance systems punish the winners - even if they're not the ones playing it.

And the other question is "should the team that lost 112-102 get more VPs than the one who lost 12-2?" If not, then we're either rewarding the losers for playing high-variance (or against high-variance) or each match is being scored on a different scale. I don't really have a problem with the latter - say "25 VPs on IMP difference, and 5 VPs on how many IMPs you let out, based on a fixed IMPs/board metric", but thousands would. And, it brings back the "you're going to be punished for playing a swingy set against the wild bidders, as opposed to the next team who gets the wild bidders on the boring flat partscores - because you won 44-30, and the next team won +5, push, push, -1, push, +6, push".
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#24 User is offline   Trinidad 

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Posted 2012-December-24, 13:33

 Fluffy, on 2012-December-22, 11:02, said:

Since this has been resurrected I will throw a random idea.

IMO a team that wins 13-2 IMPs should score better than a team that wins 113-102, not by much but by some ammount nevertheless. giving 95% VPs to IMP difference and 5% to IMP ratio could be more accurate to me.

There is no fundamental reason why 113-102 is better or worse than 13-2. If the basketball score is simply due to a large number of boards then the VP scale takes care of that already: A 13-2 score in a 4 board match leads to 15.38-4.62 VP. A score of 113-102 in a 64 board match will score 11.62-8.38. (If my calculations are correct.)

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#25 User is offline   RunemPard 

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Posted 2012-December-24, 16:38

 Trinidad, on 2012-December-24, 13:33, said:

There is no fundamental reason why 113-102 is better or worse than 13-2. If the basketball score is simply due to a large number of boards then the VP scale takes care of that already: A 13-2 score in a 4 board match leads to 15.38-4.62 VP. A score of 113-102 in a 64 board match will score 11.62-8.38. (If my calculations are correct.)

Rik



It seems pretty obvious that he is talking about both teams playing the same # of boards to me.
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#26 User is offline   barmar 

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Posted 2012-December-24, 18:45

A basketball score almost certainly has to be from a very long match.If you have a long match like that and get a score of only 13-2, it means that almost all the boards were pushes, suggesting that the two teams are about equal; that's exactly the opposite of what the high ratio would suggest.

A score like 113-102 means that you had lots of swings. But it also means that about the same number of swings went in each direction, which again suggests that the teams are about equal. The increased number of big swings suggests that both teams have some aggressive players.

If we're talking about matches of different lengths, then it would probably be appropriate to normalize the VP scale, perhaps dividing IMPs by #boards. The traditional VP scales simply have different scales for different match lengths.

#27 User is offline   aguahombre 

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Posted 2012-December-24, 18:52

On 64 boards, the winner moves on.
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#28 User is offline   barmar 

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Posted 2012-December-24, 19:21

Good point. What is the longest match played using VP scoring?

#29 User is offline   Rossoneri 

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Posted 2012-December-25, 02:08

 barmar, on 2012-December-24, 19:21, said:

Good point. What is the longest match played using VP scoring?


No idea. Probably national trials where there's a small enough pool?
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#30 User is offline   gnasher 

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Posted 2012-December-25, 05:09

 barmar, on 2012-December-24, 19:21, said:

Good point. What is the longest match played using VP scoring?

The longest I know of is the English Premier League, which has 60-board matches converted to VPs.
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#31 User is offline   Trinidad 

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Posted 2012-December-25, 05:11

 RunemPard, on 2012-December-24, 16:38, said:

It seems pretty obvious that he is talking about both teams playing the same # of boards to me.

Then the first sentence of my post is true:

Quote

There is no fundamental reason why 113-102 is better or worse than 13-2.

Rik
I want my opponents to leave my table with a smile on their face and without matchpoints on their score card - in that order.
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#32 User is offline   mgoetze 

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Posted 2013-January-03, 17:45

 Fluffy, on 2012-December-22, 11:02, said:

IMO a team that wins 13-2 IMPs should score better than a team that wins 113-102,

Given duplicated boards and matches of equal length, it seems obvious to me that the match which ended 13-2 included better bridge all around than the one which ended 113-102, and thus I would reach the opposite conclusion.
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#33 User is offline   mycroft 

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Posted 2013-January-03, 18:14

 mgoetze, on 2013-January-03, 17:45, said:

Given duplicated boards and matches of equal length, it seems obvious to me that the match which ended 13-2 included better bridge all around than the one which ended 113-102, and thus I would reach the opposite conclusion.
That I would agree with, but the match that ended 13-2 may have no better or worse bridge than the one that ended 28-17, if (as I said before) system differences meant that 2 games were played the "wrong way up" by the weak NT openers, one going down because it was wrongway, one making only because it was wrongway. Never mind the partscore issues, that's 22 IMPs on "who's on lead" that, sure, balance themselves out, but aren't going to lead to a 13-2 game.

The bridge could be *better* than the 13-2 game, but in the 13-2 game everybody was playing the same system, so the auctions and the contracts were frequently almost identical.

Also, my final questions, also above, still apply: do you punish the "high-variance" players when they win (because they tend to win 72-60 over 16 rather than 34-20) and their opponents when they lose (because they tend to lose 72-60, too)? If so, do the losers in the wild match do better because of the bad bridge (required if each match is worth the same number of VPs) or do they get punished, too (which means that wild matches score fewer VPs than low-scoring matches with the same IMP difference)? Whichever way you choose, there are problems.

Now, currently, one reason to play a non-standard system is that it's higher-variance; that more total IMPs will be scored than with the "local normal". If you're significantly better than the field, then on average not only will you still win, but you will win by more than if you were playing "local normal" (because your variance wins are wins, and your skill will minimize the variance losses you suffer, in addition to the expected wins by skill difference). That means that it is currently (where just the difference counts) an advantage for those pairs to play something different, over and above the benefits of playing the system. That might not be right, but the counteraction proposed certainly isn't any righter.
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#34 User is offline   Cascade 

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Posted 2013-January-03, 19:00

 mgoetze, on 2013-January-03, 17:45, said:

Given duplicated boards and matches of equal length, it seems obvious to me that the match which ended 13-2 included better bridge all around than the one which ended 113-102, and thus I would reach the opposite conclusion.


If its better bridge all around do you think that both sides should get better scores?
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#35 User is offline   mgoetze 

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Posted 2013-January-03, 19:10

 Cascade, on 2013-January-03, 19:00, said:

If its better bridge all around do you think that both sides should get better scores?

Nope. (Of course, as mycroft points out, there are other possible reasons for high variance than bad bridge. If it were the only possible explanation, this idea would hold more attraction, but there are still arguments to be made against it.)
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#36 User is offline   Fluffy 

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Posted 2013-January-05, 15:52

 mgoetze, on 2013-January-03, 17:45, said:

Given duplicated boards and matches of equal length, it seems obvious to me that the match which ended 13-2 included better bridge all around than the one which ended 113-102, and thus I would reach the opposite conclusion.
Sorry but looks to me you are disageeing with me just because disagreeing with me its natural for you.


You say 13-2 incluided better bridge, and thats exactly my point, 13-2 involved better bridge and a team got a well deserved victory leaking only 2 IMPs to a strong contender, the 113-102 was just loads of luck all around and something close to a tie is fair.
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#37 User is offline   mgoetze 

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Posted 2013-January-05, 16:21

 Fluffy, on 2013-January-05, 15:52, said:

Sorry but looks to me you are disageeing with me just because disagreeing with me its natural for you.


You say 13-2 incluided better bridge, and thats exactly my point, 13-2 involved better bridge and a team got a well deserved victory leaking only 2 IMPs to a strong contender, the 113-102 was just loads of luck all around and something close to a tie is fair.

No, the point is that you are only looking at it from one point of view. The VPs for the losing teams matter too...
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#38 User is offline   Hanoi5 

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Posted 2013-January-09, 15:44

When the 30 VP's scale was in use a bye got 18 VP's, how many VP's are byes getting now? Is this the table which Bali will use? Is there a link to the 'officiality' of this decision?

 wyman, on 2012-May-04, 09:48, said:

Also, he rates to not have a heart void when he leads the 3.


 rbforster, on 2012-May-20, 21:04, said:

Besides playing for fun, most people also like to play bridge to win


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#39 User is offline   jallerton 

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Posted 2013-January-26, 04:17

As 'Bye' tends to equate to 'average plus', the obvious 'Bye' score on a 20VP scale would be 12VPs.

However, that's far too simple and rumour has it that the Committee favours using one third of the cube of Pi.
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#40 User is offline   fromageGB 

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Posted 2013-January-26, 13:38

 jallerton, on 2013-January-26, 04:17, said:

As 'Bye' tends to equate to 'average plus', the obvious 'Bye' score on a 20VP scale would be 12VPs.

However, that's far too simple and rumour has it that the Committee favours using one third of the cube of Pi.

I don't see how a bye is worth anything like 12 out of 20. However, it is arguable that you should get more than just an average 10, so I would say a third of the cube of pi is about right.
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