MP vs IMPs

[PhantomSac]

<3 helene, just so you know I found this thread really interesting, didn't have anything to add to it for obvious reasons but would enjoy more posts/threads like this.

[whereagles]

yeah, but statistical services are expensive, ya know kthxbyehttp://www.bridgebase.com/forums/public/style_emoticons/default/rolleyes.gif

[nige1]

I'd be grateful if Helene_t would comment. Is the following a reasonable basis for an alternative approach to estimating the relative skill involved in MPs and cross-imps?

 

1. Work out the average rank (as a percentile) of a selection of top pairs over lots of world-class MP pairs events.
2. Also work out a their average percentiles at similar cross-imp pairs events.
3. Then see how well these two over-all rankings correlate with their rankings in each individual event. Perhaps, also future events.
4. The higher the correlation, the better the measure of skill? Especially if one form of scoring dominates the other as a predictor.

[mgoetze]

Also work out a their average percentiles at similar cross-imp pairs events.

LOL.

[helene_t]

Yes, that sounds like a good plan.

 

But you need somehow to take into account that the fields could be more homogenous in one type of events than in the other. Suppose, for example, that the skill factor is really the same at both forms of scoring, and the IMP and MP tourneys are similar w.r.t. size and balance. However, IMP tourneys attract fewer weak pairs. So the relative ranking of the top pairs will be more stable at IMPs because there is less randomness associated with sitting in the same seat as a weak pair on a particular board.

 

So unless you have data where identical fields play some IMP tourneys and also some MP tourneys, the analysis is not trivial.

[nige1]

Clarification for mgoetze: I meant, for example, that if you finish 2nd out of 300 pairs then you are in the top percentile.

 

Thank you Helene_t.

Perhaps it would be better to use the ranks of the selected pairs relative to each other and ignore all other competitors?

[helene_t]

I think we have too few flame wars about statistics. I think I will start a poll: "Are Bayesian methods better than frequentist ones?"

[whereagles]

anyone can say "this is an absolutely obv 4S bid".

 

not so with statistics :)

[mgoetze]

Clarification for nige1: there is no such thing as "lots of world-class cross-IMP pair events".

[nige1]

Clarification for nige1: there is no such thing as "lots of world-class cross-IMP pair events".

Fair enough. I thought some Calcutta and WBF events might qualify. Failing that, you'd have to settle for what is available.

[barmar]

Fair enough. I thought some Calcutta and WBF events might qualify. Failing that, you'd have to settle for what is available.

Yes, they would. But there aren't too many of them.

 

IMP-Pairs is arguably the most popular form of online bridge play -- compare the number of IMPs vs MP tables in the BBO MBC. That's probably the most telling evidence that it's an easier, or less stressful, form of the game. If you're playing with a random, you're less likely to get called an "idjit" for dropping an overtrick.

[jogs]

cherdano,

 

Maybe the link I posted was too tough for you to understand. Try this

one from the Khan Academy.

https://www.khanacademy.org/math/probability/descriptive-statistics/variance_std_deviation/v/sample-variance

 

Helene thinks double dummy analysis is an exact science. It isn't.

She thinks confidence intervals look like this ||. In bridge they

really look like this |______________|. In 7 board swiss matches

flight C teams occasionally get lucky and beat world class teams.

90% slams go down 10% of the time.

Feel free to delete your inane post.

[jogs]

Nobody can properly analyze 9000 bridge hands.

 

Madam, you are a fakir and a fraud. You are an idiot turned loose with a computer and a first year grad student's knowledge of statistics.

 

That may have been true in the past. Today with Salman Khan teaching

statistics for free in his Khan Academy, a bright high school can solve

bridge hand evaluation in little pieces at a time. None of the discrete

bridge models require knowledge of calculus.

The key in using hypothesis testing is choosing the appropriate side

conditions. When testing opening 1S vs 1NT every data entry must

have a 5332 pattern. Do not include the 5422 pattern.

 

You present a double dummy playing analysis based on a potentially very biased sample.

 

Double dummy analysis is always biased.

[helene_t]

Sigh. This study has nothing to do with DD analysis. I just evaluated two different scoring methods for mitchell movements of different size. You could apply it to figure skating or jeopardy etc, it is not specific to bridge.

 

And this talk about "bias". LOL. I just simulated some normal distributed data. If there is any bias in those data it can only be because there is a bug in the random number generator I used. I think jdeegan just thought he could impress someone by demonstrating that he can spell the word "BIAS", regardless of whether he can use it in a context where it makes sense.

 

Finally, jogs, you don't need to teach Arend and me high school statistics.

[whereagles]

helene, let's put it this way: you can't teach "standard deviation" to a person... the person is either born with it built-in.. or not :)

[nige1]

That may have been true in the past. Today with Salman Khan teaching statistics for free in his Khan Academy, a bright high school can solve bridge hand evaluation in little pieces at a time. None of the discrete bridge models require knowledge of calculus.

helene, let's put it this way: you can't teach "standard deviation" to a person... the person is either born with it built-in.. or not :)

Correcting our own or others' mistakes is fine but there's no need to impugn each others' abilities. I believe that those who are interested can understand the concept of standard-deviation, with the help of Jogs' link.

Khan's Descriptive Statistics Course

[helene_t]

Perhaps it would be better to use the ranks of the selected pairs relative to each other and ignore all other competitors?

You mean generating an mp score based on all tables involving non overlapping pairs being voided? Yes that is probably a good idea

[mgoetze]

Correcting our own or others' mistakes is fine but there's no need to impugn each other's abilities. I believe that those who are interested can understand the concept of standard-deviation, with the help of Jogs' link.

Probably, but I would doubt that just anyone can understand algebraic geometry with the help of cherdano's published papers on the subject. (Algebraic geometry makes my head hurt.)

[nige1]

You mean generating an mp score based on all tables involving non overlapping pairs being voided? Yes that is probably a good idea

No, I wish I'd meant that. Helene_t's suggestion is better. Perhaps, you could also follow her protocol with the cross-imp tournaments.

[Vampyr]

No, I wish I'd meant that. Helene_t's suggestion is better. Perhaps, you could also follow her protocol with the cross-imp tournaments.

 

What about using cross-IMP scores from a teams tournament?

[helene_t]

No, I wish I'd meant that. Helene_t's suggestion is better. Perhaps, you could also follow her protocol with the cross-imp tournaments.

Yes, you would have to follow the same protocol for XIMPs and for MPs since the purpose of the study is to make a fair comparison between the two.

[whereagles]

Correcting our own or others' mistakes is fine but there's no need to impugn each other's abilities. I believe that those who are interested can understand the concept of standard-deviation, with the help of Jogs' link.

 

I just wanted to say it's far easier for those with an analytic mind to understand the concept. The rest is rhetoric :D

 

The point was also that some people simply refuse to understand the concept. I see this happening over and over again: "Why were my two finesses wrong? At least one should have been right. The deck was fixed. Damn these computer hands!!!!" :)

[jogs]

Probably, but I would doubt that just anyone can understand algebraic geometry with the help of cherdano's published papers on the subject. (Algebraic geometry makes my head hurt.)

 

You only need a complete understanding of algebra. No need to know geometry.

[helene_t]

You only need a complete understanding of algebra. No need to know geometry.

Q.F.T. I don't think there is anyone on this planet with a complete understanding of algebra.

 

I didn't attempt to read Arend's thesis so I can't say that you are wrong. I suspect that you don't know what algebraic geometry is, though. (Hint: it doesn't have much to do with geometry except in a very abstract sense).

[PhilKing]

Q.F.T. I don't think there is anyone on this planet with a complete understanding of algebra.

 

I didn't attempt to read Arend's thesis so I can't say that you are wrong. I suspect that you don't know what algebraic geometry is, though. (Hint: it doesn't have much to do with geometry except in a very abstract sense).

 

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