player skill rank

[scarletv]

Suppose you are captain of a team of four strangers, two advanced ones and two intermediate ones. What would partnership compatibility mean in that context? If "intermediate" means "understanding one's own system" while "advanced" means "understanding a wide range of systems", probably you should pair each intermediate with an advanced partner. Unless, maybe, if there is a local standard which both intermediates can be assumed to play.

If there is a national standard established. When I refer to the clubs where I play I can tell you that there is a wide variety of systems and no standard system (at least 4 versions of Forum, Große-Kleine-Treff, Kleine Treff, so called Standard American, Acol, Swiss Acol, 2/1 Turkish style, Precision, even Truscott found the way to our club last week). So where is the compatibility bonus coming from?

[barmar]

Suppose you are captain of a team of four strangers, two advanced ones and two intermediate ones. What would partnership compatibility mean in that context? If "intermediate" means "understanding one's own system" while "advanced" means "understanding a wide range of systems", probably you should pair each intermediate with an advanced partner. Unless, maybe, if there is a local standard which both intermediates can be assumed to play.

 

That's kind of what I was getting at earlier. An advanced player knows enough that they can play comfortably with a variety of different partners -- he can usually adjust to their system. An intermediate player knows a limited amount of stuff, and is still building up his repertoire.

 

But this isn't necessarily the only way to measure skill. Consider someone who has been playing kitchen bridge for a lifetime. They may know just a handful of conventions, but they could be extremely successful with them. Furthermore, cardplay is the same for everyone -- it's harder to measure what you "know" about it (although something like Bridge Master 2000 could be a good way to assess this).

[Vampyr]

If "intermediate" means "understanding one's own system" while "advanced" means "understanding a wide range of systems"

 

This doesn't seem like a very useful measure. Even a non-player could understand a wide range of systems.

[barmar]

This doesn't seem like a very useful measure. Even a non-player could understand a wide range of systems.

 

What does that mean? It sounds like saying someone speaks French because they've memorized an English-to-French dictionary, although they've never actually had a conversation in the language.

[FM75]

How something is distributed always depends on what plotted along the x-axis. Any continuous distribution can be corrected to a normal distribution with a normalisation function.

 

Take, as an example, the distribution of the diameter of the particles in a powder (sand, powdered sugar, etc.), measured in meters (mm, µm, whatever). In most powders, this distribution is heavily skewed: there are many small particles and few large ones. However, if you plot the log of the particle size, then many natural particle size distributions are normal. This is typically not true for the powders you have at home since they are sieved, cutting off the distribution.

 

 

Rik

It is funny that you did not rethink the assertion that "any continuous distribution can be corrected to a normal distribution ...", after your powder example.

 

First of all, by definition a Gaussian (normal) distribution is defined as a function over the domain of all real numbers.

 

In any event, the universe is full of non-Gaussian distributions - The energy density as a function of frequency of a black body and the energy levels of electrons in an atom spring immediately to mind. In fact, any measurement that is bounded for any reason, for example temperature, can't fit a Gaussian distribution. The age of all of the members of any particular species - yes, non-Gaussian.

 

That said, I can't imagine a reason for imposing a gaussian distribution model on a player skill ranking at anything - except that perhaps the person making the measurement plans for the results to be Gaussian and is willing to skew the measurements in some way to "make them fit" his postulated distribution function.

[Vampyr]

What does that mean? It sounds like saying someone speaks French because they've memorized an English-to-French dictionary, although they've never actually had a conversation in the language.

 

Understanding bidding systems does not indicate that a person is even a good bidder, judgment being more important in this area; nor does it indicate that the player can declare or defend competently.

[Zelandakh]

Understanding bidding systems does not indicate that a person is even a good bidder, judgment being more important in this area; nor does it indicate that the player can declare or defend competently.

Quite so. When I learned to play bridge I did so alone from books. It was many years before I actually played with people. During that time I wrote out the bidding systems and understood how they worked, indeed even combined ideas I liked from various places and created my own. It was probably similar to the way computers operate bidding rules. But with no practical experience you could say that I had no judgement whatsoever and was truly awful at card play.

 

Now I still think about system structures and have the computer-like rules in mind but hopefully at least have added a little bit of judgement. And improving the system rules helps the judgement since the hands are better defined. Sadly the card play is still pretty terrible but perhaps one day the posts from BBFers will rub off on me. :)

[barmar]

I don't think the criteria are intended to be applied indiscriminately. They assume the typical way that players advance in experience. They start off with little playing experience and instruction in a few basic conventions. Over time, they get more experience playing, and usually also learn more conventions to improve their bidding, or at least be able to play competently with and against players who want to play those conventions (e.g. you might not agree that Flannery is a good convention, but being able to play it means Hamman is a potential partner).

 

So knowledge of many conventions doesn't necessarily mean that you're a great player, but being able to use them effectively is a strong indicator.

 

 

Thus, my analogy with languages. It's not enough to know the meaning of words in a language, you need to be able to have meaningful, fluent conversations to be considered to "know" the language.

[larlar]

jec has an adjustment of -0.28 - he needs to come to the Acol Club and play against the real experts! :lol:

 

Meanwhile jack has an adjustment of +0.1 and a Total Score above both Jimmy and Justin. I eagerly await his appearance in the next Bermuda Bowl.

 

 

pfft http://bboskill.com/user/phantomsac :P

[Bbradley62]

pfft http://bboskill.com/user/phantomsac :P

Maybe I'm a little dense. Why is that funny? Because of 0 adjustment?

[diana_eva]

Maybe I'm a little dense. Why is that funny? Because of 0 adjustment?

 

I suppose bec phantomsac is Justin.

[Bbradley62]

I'm well aware of that. And bboskill rates him as "World Class". Seems right to me.

[Zelandakh]

And he does not play in the Acol Club? Amazing! :lol:

[1eyedjack]

"He" has not played for a couple of months. At least not as "he". Being outed does that to you, perhaps.

[NickRW]

On the normal distribution thing... Assuming you accept the EBU's skill rating system as reasonable (I haven't heard of anything better personally), then it is skewed normal with a heavy tail (that I imagine is there because the graph includes many "non mature" grades). See

https://www.ebu.co.uk/ngs/stats

 

Nick

[StevenG]

On the normal distribution thing... Assuming you accept the EBU's skill rating system as reasonable (I haven't heard of anything better personally), then it is skewed normal with a heavy tail (that I imagine is there because the graph includes many "non mature" grades). See

https://www.ebu.co.uk/ngs/stats

The graph would look very normal if the 2 grade was subdivided as the Ace grade is. However, that is probably the result of adding a lot of variables together. Given that distribution of match points on a typical club night looks vaguely normal, adding together lots of these distributions is going to tend to something much more like a normal distribution.

 

Imagine that every adult in the country was forced to play club bridge for a year. I would expect the EBU gradings distribution would still look normal, but if you extracted the grades for the current club players, i.e. those who have an aptitude and/or interest in the game, their data would now not be normal at all, but a subset of the high ability tail.

[kenberg]

Question happily withdrawn.