[mtvesuvius]

cherdanno, on Apr 3 2009, 11:37 AM, said:

jdonn, on Apr 3 2009, 11:09 AM, said:

This really seems simple. Matchpoints is more accurate at choosing the best matchpoint pair than imps is at choosing the best imp pair (in the same amount of boards). I agree with that. But matchpoints is NOT more accurate at choosing the best imps pair than imps is at choosing the best imp pair. Unprovable I know, but I would stake anything on it.

If anyone can come up with a method to validate this claim (this isn't impossible, given enough data) I am happy to bet that a 3-session MP event is better at determining the 6 best pairs than a 3-session IMP event.

It may be, but I don't think it's practical to select pairs who are good at MPs for an IMP event.

[Walddk]

jdonn, on Apr 3 2009, 06:09 PM, said:

This really seems simple. Matchpoints is more accurate at choosing the best matchpoint pair than imps is at choosing the best imp pair (in the same amount of boards). I agree with that. But matchpoints is NOT more accurate at choosing the best imps pair than imps is at choosing the best imp pair. Unprovable I know, but I would stake anything on it.

It is simple. Let's just look at the following familar example:

♥ AQxxx

♥ xxxx

This is your trump suit in 6♥, and you can afford to lose a trick and still make the contract. Now, a priori at IMPs the correct play is to cash the ace first, then enter your hand and lead a small up. You improve your odds, because it caters to the singleton king offside.

At matchpoints, however, that would be an incorrect line. You need to try for as many tricks as possible, and you can escape for no loser every time LHO is dealt Kx. You can't afford the luxury of the safety play (cashing the ace first) with the format you are going to use.

If Kx happens to be onside, you have blown a trick by adopting a safety play line and will get a bottom at MP, but the fact of the matter is that you know how to play IMPs, and that is the crucial point.

I mean, you are going to select pairs for an IMP event, are you not? So what good is it that some pairs can take lots of tricks at MP if they don't know how to tackle a suit like this at IMPs? If they don't, you won't know until it's too late.

Roland

[jdonn]

cherdanno, on Apr 3 2009, 11:37 AM, said:

jdonn, on Apr 3 2009, 11:09 AM, said:

This really seems simple. Matchpoints is more accurate at choosing the best matchpoint pair than imps is at choosing the best imp pair (in the same amount of boards). I agree with that. But matchpoints is NOT more accurate at choosing the best imps pair than imps is at choosing the best imp pair. Unprovable I know, but I would stake anything on it.

If anyone can come up with a method to validate this claim (this isn't impossible, given enough data) I am happy to bet that a 3-session MP event is better at determining the 6 best IMP pairs than a 3-session IMP event.

Then why has this not always been done?

[cherdanno]

jdonn, on Apr 3 2009, 11:53 AM, said:

cherdanno, on Apr 3 2009, 11:37 AM, said:

jdonn, on Apr 3 2009, 11:09 AM, said:

This really seems simple. Matchpoints is more accurate at choosing the best matchpoint pair than imps is at choosing the best imp pair (in the same amount of boards). I agree with that. But matchpoints is NOT more accurate at choosing the best imps pair than imps is at choosing the best imp pair. Unprovable I know, but I would stake anything on it.

If anyone can come up with a method to validate this claim (this isn't impossible, given enough data) I am happy to bet that a 3-session MP event is better at determining the 6 best IMP pairs than a 3-session IMP event.

Then why has this not always been done?

Because usually there is more time than 3 sessions to select two teams?

[helene_t]

jdonn, on Apr 3 2009, 05:53 PM, said:

Then why has this not always been done?

lol

[jdonn]

cherdanno, on Apr 3 2009, 11:55 AM, said:

jdonn, on Apr 3 2009, 11:53 AM, said:

cherdanno, on Apr 3 2009, 11:37 AM, said:

jdonn, on Apr 3 2009, 11:09 AM, said:

This really seems simple. Matchpoints is more accurate at choosing the best matchpoint pair than imps is at choosing the best imp pair (in the same amount of boards). I agree with that. But matchpoints is NOT more accurate at choosing the best imps pair than imps is at choosing the best imp pair. Unprovable I know, but I would stake anything on it.

If anyone can come up with a method to validate this claim (this isn't impossible, given enough data) I am happy to bet that a 3-session MP event is better at determining the 6 best IMP pairs than a 3-session IMP event.

Then why has this not always been done?

Because usually there is more time than 3 sessions to select two teams?

I think 4 sessions has been extremely common in the past. Is 3.5 sessions the cutoff where imps are a better selection method?

Frankly I don't see why they don't do more than 3 sessions now when playing online should allow for more sessions than usual instead of fewer, but I'm sure there must be a reason.

[hrothgar]

cherdanno, on Apr 3 2009, 07:37 PM, said:

jdonn, on Apr 3 2009, 11:09 AM, said:

This really seems simple. Matchpoints is more accurate at choosing the best matchpoint pair than imps is at choosing the best imp pair (in the same amount of boards). I agree with that. But matchpoints is NOT more accurate at choosing the best imps pair than imps is at choosing the best imp pair. Unprovable I know, but I would stake anything on it.

If anyone can come up with a method to validate this claim (this isn't impossible, given enough data) I am happy to bet that a 3-session MP event is better at determining the 6 best IMP pairs than a 3-session IMP event.

Han / Josh

One way to approach this problem would be to analyze the variance in board results for (comparable) IMPS pairs and MP pairs events.

As we've discussed before, variance in board results negatively impacts a tournament's ability to identify the "top" pairs. In theory, if we could characterize the impact of the change in format on variance, we might be able to arrive at some ball park estimates for other parts of the model.

For example, we might be able to say

Switching from MP pairs to IMP pairs increases variance by X

In order to "break even", the IMP pairs format would need to be at least Y times better at identifying good IMP players than a MP pairs format.

If Y is very very large, stick with MP pairs.
If Y is very very small, go with IMP pairs.

[helene_t]

That's easy enough, the difficult thing is to estimate the correlation between a pair's performance at MPs and its performance at IMPs.

[mtvesuvius]

Also, what about U21s if attendance warrants? or is the USBF just planning on sending an U26 team? Also... This is trials for the Team Events... What about pair events?

[kfay]

Why not just send the team that wins the qualifiers in DC?

[karlson]

I really don't get all the griping about MP. Surely a pair that is significantly better than the rest of the field is going to be fine regardless of the format?

I'd be really happy with the fact that random gifts won't account for 20 imps myself.

By far the best aspect of having it online is that people who would never normally spend the money and time to come out to DC or whatever for the trials are going to have a chance to play. Who cares if they have no shot at winning, at least they get an idea of the level they would need to get to, and maybe some of them won't think it's a hopeless endeavor.

[olien]

Well, I think the idea of MP trials is not the way to go. As has been previously mentioned, what is the point of an MP trial for an IMPs contest?

Anyways, the idea of having to require people to go to a club is impractical. Who will have all day on Saturday and half a day on Sunday to watch? Family should be excluded as potential proctors because of the potential conflict of interest.

Maybe I'm paranoid, who knows, but the entire format and setup seems to be a farce, too many holes that people could complain about after the fact.

[JanM]

kfay, on Apr 3 2009, 01:11 PM, said:

Why not just send the team that wins the qualifiers in DC?

Because that is too late an event. The DC Trials are July 22-24, the Istanbul Championship is Aug. 15-23

[mike777]

JanM, on Apr 3 2009, 07:15 PM, said:

kfay, on Apr 3 2009, 01:11 PM, said:

Why not just send the team that wins the qualifiers in DC?

Because that is too late an event. The DC Trials are July 22-24, the Istanbul Championship is Aug. 15-23

As a side note if the 2009 World youth championship is in August of 2009 when is the 2010/11 youth events and when are the trials? Is there enough time?

Should these DC trials be for 2010/11; perhaps not, just a suggestion.

[georgeac]

Are all USA juniors open to play? If so, and a junior pair that enters(myself and one of my friends) does well enough to make the team but has no right really being on the team by qualifications, what happens then. It seems selection would be better than having the chance that some unqualified juniors make up the final team.

[whereagles]

Walddk, on Apr 3 2009, 04:11 AM, said:

JLOL, on Apr 3 2009, 04:29 AM, said:

Interesting

Interesting indeed. Matchpoint scoring to select the pairs for a teams event!? I am lost.

Roland

Welcome to Portugal. We got that as well in a stage of the team trials. Absolutely ridiculous.

[PeterGill]

I think the over-reaction to the use of matchpoints is backed up more by emotional reactions than by actual facts, especially by some younger posters.

The Australian Youth Pairs is the curtain raiser of our annual Youth Bridge Week, which has been held every January for 41 years. Saturday is 2 sessions of matchpoint Pairs Qualifying, then 2 sessions of the Pairs Final (match pionted) and Consolation on the Sunday, followed by the barbecue and cricket match.

I just looked through the results of the Youth Pairs from 2001 to 2009 at
http://www.abf.com.a.../pastindex.html

The top-scoring six or seven pairs in the Final in each of these nine years
are consistently among the best ten pairs in the event, with the top-scoring
three pairs usually being among the best five pairs in the event.

This data strongly suggests to me that matchpointed yotuh events do
sort out the best players efficiently in a quick time. I think it takes a
(much) longer time for imp pairs events to sort out a youth field efficiently.

I would expect similar results if I did a similar analysis of the World Junior Pairs, which also is matchpointed.

Peter Gill
Australia.

[karlson]

georgeac, on Apr 4 2009, 02:21 AM, said:

Are all USA juniors open to play? If so, and a junior pair that enters(myself and one of my friends) does well enough to make the team but has no right really being on the team by qualifications, what happens then. It seems selection would be better than having the chance that some unqualified juniors make up the final team.

Why would you think you're unqualified?

The answer is, you have a great experience and maybe next time won't feel like a fluke.

[JanM]

mike777, on Apr 3 2009, 10:41 PM, said:

JanM, on Apr 3 2009, 07:15 PM, said:

kfay, on Apr 3 2009, 01:11 PM, said:

Why not just send the team that wins the qualifiers in DC?

Because that is too late an event. The DC Trials are July 22-24, the Istanbul Championship is Aug. 15-23

As a side note if the 2009 World youth championship is in August of 2009 when is the 2010/11 youth events and when are the trials? Is there enough time?

Should these DC trials be for 2010/11; perhaps not, just a suggestion.

The DC Trials are for 2010. We do not yet know where and when the 2010 World Junior Championships will be held.

[georgeac]

karlson, on Apr 4 2009, 12:43 PM, said:

georgeac, on Apr 4 2009, 02:21 AM, said:

Are all USA juniors open to play? If so, and a junior pair that enters(myself and one of my friends) does well enough to make the team but has no right really being on the team by qualifications, what happens then. It seems selection would be better than having the chance that some unqualified juniors make up the final team.

Why would you think you're unqualified?

The answer is, you have a great experience and maybe next time won't feel like a fluke.

maybe i worded it poorly. it was late last night. anyways. maybe not that i am underqualified but shouldnt be the point of the trials be to send the best possible teams with a chance of winning. i know there are lots of juniors that are much better than i am. so shouldnt they be the ones to go to have the best chance of winning the event? just saying that one pairs trials doesnt seem like the best way to do this. with the time constraints though i guess its the only way for this year.