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Hand Evaluation

#21bluejak

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Posted 2012-February-08, 10:46

And they might be?

Players find it easiest and reasonable.

Customer service is important in running this game.

I direct and used to run a major inter-County team of eight. Last time we tried feedback, one of the questions was whether we should change the form of scoring from teams-of-eight to two teams-of four. No change was nearly unanimous.
David Stevenson

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Visiting IBLF from time to time
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Posted 2012-February-08, 12:31

Nobody says that you have to score it as two team of four matches. That would be a bad idea, because it is complicated for the players. (Not to mention that the result depends on what tables are combined into the two matches.)

But it is very easy to come up with an IMP scale for teams of 8: Take the standard IMP scale and multiply the results by the square root of 2 (= sqrt (8/4) ).

The start of such an IMP scale would then be:
IMPs   Old scale   New scale
0       0-10        0-10    (10*sqrt(2)=14 -> 10)
1      20-40       20-50    (40*sqrt(2)=57 -> 60)
2      50-80      60-110    (80*sqrt(2)=113 -> 110)
3     90-120     120-170    (120*sqrt(2)=170 -> 170)

etc.

If you would like to play teams of 6, you just adjust by sqrt(1.5)

This method is just as easy, and more reasonable if your aim is to mimic team of four scoring.

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.
The most exciting phrase to hear in science, the one that heralds the new discoveries, is not “Eureka!” (I found it!), but “That’s funny…” – Isaac Asimov
The only reason God did not put "Thou shalt mind thine own business" in the Ten Commandments was that He thought that it was too obvious to need stating. - Kenberg
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#23bluejak

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Posted 2012-February-09, 06:57

Now that's a way to really upset the customers. No-one wants a different imp scale.
David Stevenson

Merseyside England UK
EBL TD
Currently at home
Visiting IBLF from time to time
<webjak666@gmail.com>
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#24mjj29

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Posted 2012-February-09, 08:28

bluejak, on 2012-February-09, 06:57, said:

Now that's a way to really upset the customers. No-one wants a different imp scale.

Oh, I don't doubt that lots of the players are happy with the method of scoring. That has no bearing on whether or not it's illogical
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Posted 2012-February-09, 08:29

bluejak, on 2012-February-09, 06:57, said:

Now that's a way to really upset the customers. No-one wants a different imp scale.

I get the idea that you don't understand the point.

F0rdy and campboy clearly showed that, by applying the team of four IMP table to teams of 8, you are changing the IMP scale. They showed that the scoring gets "warped" when you use the team of four IMP scale for team of eight games. The team of four IMP table was never meant for teams of eight. (Just think what this would do if someone would organize a "team of 400" match: On each board 24 IMPs are exchanged.)

My post was showing that it is very easy to adapt the existing IMP scale for teams of 6, 8, 10 or 400, in such a way that this "warp" is compensated for. This doesn't make it a different IMP scale. It is the exact same IMP scale, but now for another number of participants on the team.

And don't tell me that everyone wants to stick to the numbers on the IMP scale because they know these numbers by heart.

Mathematicians, statisticians and engineers know these kind of methods as "scaling". Statisticians use scaling by averages and standard deviations to make complicated things fit in simple models; engineers use scaling to extrapolate what happens in a 100 ml beaker to what happens in a 10 m3 reactor. It means that you create rules that are independent of the scale of what you are doing. These rules are constructed in such a way that the underlying basic principles (rather than the actual numbers) are kept intact.

I can see that scaling in such an abstract thing as bridge scoring may appear confusing, but it is simply a question of doing things right. You could think about scaling in everyday life and how silly it would be if you wouldn't scale properly. You wouldn't try to let a model train of scale HO ride on a track made for a full scale train, would you? And I don't think that you would feed your cats an antilope (even though their bigger sized cousins in Africa would be happy with one). Would you apply the recipe for 12 cup cakes if you would need to make 120?

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.
The most exciting phrase to hear in science, the one that heralds the new discoveries, is not “Eureka!” (I found it!), but “That’s funny…” – Isaac Asimov
The only reason God did not put "Thou shalt mind thine own business" in the Ten Commandments was that He thought that it was too obvious to need stating. - Kenberg
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#26campboy

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Posted 2012-February-09, 09:16

bluejak, on 2012-February-09, 06:57, said:

Now that's a way to really upset the customers. No-one wants a different imp scale.

Trinidad's suggestion is easy to implement without changing the IMP scale at all. Just add the four scores, multiply by 0.7, then IMP the result.

Anyway, I don't think anyone is disputing that it is better to use an illogical system players like than a logical system they dislike.
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Posted 2012-February-09, 09:39

campboy, on 2012-February-09, 09:16, said:

Trinidad's suggestion is easy to implement without changing the IMP scale at all. Just add the four scores, multiply by 0.7, then IMP the result.

That is true, but it means that the players need to do the work (over and over again: each team, for each board). Adjusting the IMP table would mean that the TD does the work once.

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.
The most exciting phrase to hear in science, the one that heralds the new discoveries, is not “Eureka!” (I found it!), but “That’s funny…” – Isaac Asimov
The only reason God did not put "Thou shalt mind thine own business" in the Ten Commandments was that He thought that it was too obvious to need stating. - Kenberg
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#28CamHenry

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Posted 2012-February-09, 09:45

campboy, on 2012-February-09, 09:16, said:

Trinidad's suggestion is easy to implement without changing the IMP scale at all. Just add the four scores, multiply by 0.7, then IMP the result.

Anyway, I don't think anyone is disputing that it is better to use an illogical system players like than a logical system they dislike.

campboy, I'm not convinced many players - ECL or otherwise - will want to multiply by 0.7, as it looks far too much like "take away the number you first thought of".

But yes, ECL scoring is illogical and absurd - the UBC sometimes even pulls off a win!
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#29bluejak

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Posted 2012-February-09, 09:47

When you decide whether something is "logical" in its use in an event, I believe the wishes of the majority are important. To have something that a minority think correct because they think it logical does not make it logical. Logic means something follows from something else: I think it is logical to use something people believe in, rather than something that a few mathematically inclined people construct.
David Stevenson

Merseyside England UK
EBL TD
Currently at home
Visiting IBLF from time to time
<webjak666@gmail.com>
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#30campboy

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Posted 2012-February-09, 10:09

I do not think that something is logical simply because it follows from something else unless the thing it follows from is itself logical.
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#31PeterAlan

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Posted 2012-February-09, 10:10

bluejak, on 2012-February-09, 09:47, said:

When you decide whether something is "logical" in its use in an event, I believe the wishes of the majority are important. To have something that a minority think correct because they think it logical does not make it logical. Logic means something follows from something else: I think it is logical to use something people believe in, rather than something that a few mathematically inclined people construct.

But we already do a whole lot of things because they are mathematically right, despite the fact that the vast majority of players do not know why or even believe that it is logical - perhaps arrow switching 1/8 of the boards played in a Mitchell is the most obvious example. At least 90% of players don't understand this, yet I'm quite sure that most would understand it perfectly easily if told there's one IMP table for teams of 4 and another for teams of 8. They're already used to variations in VP scales.

I'm pedantic enough to diasgree fundamentally with your interpretation of the word "logical". The notion that "something people believe in" is therefore "logical"? - apply this to religious beliefs, and the many and conflicting varieties thereof, and you'll see what an absurd statement it is.
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#32barmar

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Posted 2012-February-09, 10:39

PeterAlan, on 2012-February-09, 10:10, said:

I'm pedantic enough to diasgree fundamentally with your interpretation of the word "logical". The notion that "something people believe in" is therefore "logical"? - apply this to religious beliefs, and the many and conflicting varieties thereof, and you'll see what an absurd statement it is.

But many people who believe would probably say otherwise. Who gets to dictate what's logical?

Actually, the use of "logical" for this discussion is fundamentally different from using it in a pure mathematical or scientific context. Bridge scoring is not something you can decide the truth or falsity of. You may be able to decide whether it's fair. However, in this particular case, I think logical is being used to mean "reasonable" -- in that case, belief is an appropriate way to judge it. Or it could mean "consistent with similar forms of the game", and then you have to decide how important this is.

#33PeterAlan

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Posted 2012-February-09, 11:25

barmar, on 2012-February-09, 10:39, said:

But many people who believe would probably say otherwise. Who gets to dictate what's logical?

I chose the example I did because there are plenty of people with conflicting beliefs out there and it can not therefore be appropriate to attach "logical" to one belief position (ie a matter of faith, without evidential support) without being prepared to do so to the other. And then you get logical contradiction; so "logical" it wasn't.

[This is entirely without prejudice to any religious beliefs, or lack of them, that I or any other posters may hold, about which I am saying nothing whatsoever.]

barmar, on 2012-February-09, 10:39, said:

Actually, the use of "logical" for this discussion is fundamentally different from using it in a pure mathematical or scientific context. Bridge scoring is not something you can decide the truth or falsity of. You may be able to decide whether it's fair.

I don't know what you mean about the truth or falsity of bridge scoring, but it's certainly something about which you can say what is mathematically appropriate. I find the thrust of bluejack's argument very strange - it's precisely on such technical matters that ordinary players expect the regulatory authorities to take a lead and sort out the relevant technical issues on their behalf. Instead, he wants to abdicate that leadership role, apparently on the grounds that "100,000 lemmings can't be wrong". [And before anyone goes there, I'm fully aware of the questions about the veracity of lemming suicide.]

barmar, on 2012-February-09, 10:39, said:

However, in this particular case, I think logical is being used to mean "reasonable" -- in that case, belief is an appropriate way to judge it. Or it could mean "consistent with similar forms of the game", and then you have to decide how important this is.

Indeed. So use "reasonable" or "sensible" and don't go on arguing that "logical" is right.
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Posted 2012-February-09, 11:29

IMO, what is logical is not so relevant. I would think that "being consistent" is relevant.

If you want to be consistent when it comes to the fundamentals of IMP games, you use an adjusted IMP scale.

If you want to be consistent when it comes to the numbers on the teams of four IMP table, you also use this table for teams of eight scoring.

Whatever you chose is fine with me. Both methods are fair, as long as the contestants are informed ahead of time of the conditions.

But it would be good to realize that chosing the second option is equivalent to saying that a train has 64 wheels, because the 9:15 train from Reading to London has 64 wheels. The only thing I have done is hand a method to calculate the number of wheels on the train, depending on its length, making sure that the train looks like a train when it has 2 cars and when it has 24. Some might think that this complicates life. I think it makes life a lot easier when the number of wheels on a train depends on the number of cars. But what is needed for that is the notion that it is not the number of wheels that makes a train a train, but rather the amount of wheels per car and the fact that it moves on a track.

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.
The most exciting phrase to hear in science, the one that heralds the new discoveries, is not “Eureka!” (I found it!), but “That’s funny…” – Isaac Asimov
The only reason God did not put "Thou shalt mind thine own business" in the Ten Commandments was that He thought that it was too obvious to need stating. - Kenberg
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Posted 2012-February-09, 11:48

bluejak, on 2012-February-08, 10:46, said:

Players find it easiest and reasonable.

Customer service is important in running this game.

Now, essentially what happened in this thread is that you got a minor customer complaint ("the illogical way"). You asked why this particular customer felt this way (excellent customer service). And because of this, you got constructive feedback.

Then, you seem to discard the feedback, "because your customers don't feel like that":

bluejak, on 2012-February-08, 10:46, said:

I direct and used to run a major inter-County team of eight. Last time we tried feedback, one of the questions was whether we should change the form of scoring from teams-of-eight to two teams-of four. No change was nearly unanimous.
Whereas in reality, your customers have only said that they preferred the bad thing (adding the scores, IMPing using the team of four IMP table) over something even worse (dividing into two teams of four matches).

Maybe the next time you ask for feedback you could ask the customers whether they want to use the IMP table with the numbers for a team of four match which leads to "bending of the IMP scale" at places where it wasn't meant to bend or whether they want to use the IMP table that is specifically designed for a team of eight match where the principle of IMP scoring is kept correctly, but the actual numbers are different from the team of four table (equivalent to the different VP tables for different numbers of boards).

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.
The most exciting phrase to hear in science, the one that heralds the new discoveries, is not “Eureka!” (I found it!), but “That’s funny…” – Isaac Asimov
The only reason God did not put "Thou shalt mind thine own business" in the Ten Commandments was that He thought that it was too obvious to need stating. - Kenberg
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#36barmar

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Posted 2012-February-09, 14:17

PeterAlan, on 2012-February-09, 11:25, said:

I don't know what you mean about the truth or falsity of bridge scoring, but it's certainly something about which you can say what is mathematically appropriate.

Scoring a game is essentially arbitrary, it can be done any way the game designers want.

However, if they declare a specific set of goals for the scoring system, you can determine whether the scoring system achieves those goals. That could be a "logic" of scoring.

For instance, when the rules for doubled undertricks was changed, it was because players and administrators felt that the old rules made it too easy to sacrifice. That feeling was a popularity issue, but the scoring changes were a logical consequence.

#37AlexJonson

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Posted 2012-February-09, 14:48

barmar, on 2012-February-09, 14:17, said:

Scoring a game is essentially arbitrary, it can be done any way the game designers want.

However, if they declare a specific set of goals for the scoring system, you can determine whether the scoring system achieves those goals. That could be a "logic" of scoring.

For instance, when the rules for doubled undertricks was changed, it was because players and administrators felt that the old rules made it too easy to sacrifice. That feeling was a popularity issue, but the scoring changes were a logical consequence.

One hates to be argumentative, but you are equating the word reasonable with the word logical. Not a good idea.
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#38PeterAlan

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Posted 2012-February-09, 18:16

barmar, on 2012-February-09, 14:17, said:

Scoring a game is essentially arbitrary, it can be done any way the game designers want.

However, if they declare a specific set of goals for the scoring system, you can determine whether the scoring system achieves those goals. That could be a "logic" of scoring.

For instance, when the rules for doubled undertricks was changed, it was because players and administrators felt that the old rules made it too easy to sacrifice. That feeling was a popularity issue, but the scoring changes were a logical consequence.

You seem to be confusing the underlying scoring structure of the game, which for argument's sake I'm prepared to accept as being wholly arbitrary, with the issue here, which is the appropriate way of combining a collection of such scores, whatever they may happen to be, to produce a single score.

When the underlying scoring system is such as it is in bridge, and the independence of the events is as it is, this process is one that is reasonably well understood mathematically (statistically, if you prefer). What's being said here is that if this particular way of combining N scores meets certain desirable statistical criteria, as we suppose is the case with the standard IMP scale, then combining 2N such scores in the same way won't continue to meet those same desirable criteria, and there's no point in pretending that it will.
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#39Vampyr

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Posted 2012-February-09, 18:58

PeterAlan, on 2012-February-09, 18:16, said:

What's being said here is that if this particular way of combining N scores meets certain desirable statistical criteria, as we suppose is the case with the standard IMP scale, then combining 2N such scores in the same way won't continue to meet those same desirable criteria, and there's no point in pretending that it will.

Why does this matter if it meets other desirable criteria, chiefly that the players are used to it and like it?
I know not with what weapons World War III will be fought, but World War IV will be fought with sticks and stones -- Albert Einstein
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#40barmar

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Posted 2012-February-09, 19:10

PeterAlan, on 2012-February-09, 18:16, said:

You seem to be confusing the underlying scoring structure of the game, which for argument's sake I'm prepared to accept as being wholly arbitrary, with the issue here, which is the appropriate way of combining a collection of such scores, whatever they may happen to be, to produce a single score.

I was using the underlying scoring structure as an example, but didn't think I was equating them.

Quote

When the underlying scoring system is such as it is in bridge, and the independence of the events is as it is, this process is one that is reasonably well understood mathematically (statistically, if you prefer). What's being said here is that if this particular way of combining N scores meets certain desirable statistical criteria, as we suppose is the case with the standard IMP scale, then combining 2N such scores in the same way won't continue to meet those same desirable criteria, and there's no point in pretending that it will.

True, it doesn't meet the same criteria, but who says it should?

I'm not familiar with teams-of-8 (AFAIK, they're not played much on this side of the pond). But it sounds like the controversy is not too dissimilar from whether IMP Pairs should be scores as cross-IMPs or versus a datum. For many years the datum method was mostly used, I think simply because it was easier when scoring by hand; computers can easily calculate cross-IMPs, and it's considered more consistent with the design of the IMP scale, so it's now most common.