[CSGibson]

Hi. I'm on my unit board, and we're thinking about having a two session cross imp pairs event for one of our sectionals this year. Any thoughts on that style of scoring, and it's appropriateness for the club level (which are the majority of players who would come out)?

[ArtK78]

Sure. It is a change from matchpoint scoring, and something different is almost always a good idea.

My unit used to run IMP pair games at its sectionals every so often, but, for some reason, they are no longer run. I guess the old guard insisted on matchpoints.

IMP pairs is different. I refer to it as matchpoints on steroids. Unlike matchpoint pairs, each board does not count the same as every other board. Game and slam hands count much more than part score deals, and you can get incredibly unlucky through no fault of your own - such as when your opponents bid a making slam that no one else bids (or stay out of a failing slam that everyone else bids).

You should try it. If you don't like it, you can always go back to matchpoints.

[jeffford76]

Our unit runs one per year. I've encountered people as late as round 11 that thought we were playing matchpoints.

It's even more important than for matchpoint events that people play the same boards, but that hasn't prevented us having 36 boards in play.

That said, it's a fun change of pace, although it's hard to take the results too seriously.

[Vampyr]

jeffford76, on May 14 2010, 04:51 PM, said:

It's even more important than for matchpoint events that people play the same boards, but that hasn't prevented us having 36 boards in play.

At our local weekly game, there is an arrow-switch. I have long lobbied for a 2-winner game or at least just using the Greek method; arrow-switching is a ridiculous randomiser.

[Gerben42]

If you arrow-switch correctly it's not a randomiser. I think 2-winner games are something to be avoided at all cost. Players want to know where they rank against all who are present, not just of their direction (cleverly avoiding comparison with their rivals / friends / whatever).

In a normal club game (12 / 13 rounds), arrow-switch the last two rounds.

A bigger problem with Mitchell games is that you are rather inflexible to have about the same number of rounds as tables.

[gordontd]

Gerben42, on May 16 2010, 07:07 PM, said:

A bigger problem with Mitchell games is that you are rather inflexible to have about the same number of rounds as tables.

Bridgemates & duplicated boards make it feasible to use Bowman movements, so that you can have two more tables than boardsets. And Web movements allow you to play thirteen sets of boards with any number of tables from 13 to 26.

[helene_t]

XIMPs is fine but IMHO it doesn't matter much whether you use XIMPs or matchpoints. My guess would be that XIMPs is slightly more efficient in terms of identifying the best pair in small fields while MPs is probably better in large fields. In any case it doesn't matter much.

But there will always be some pairs who have preference for IMPs so if competing events are generally either IMP teams or MP pairs it is probably a good idea to offer XIMPs so you have something the competitors don't have.

[gnasher]

gordontd, on May 16 2010, 08:40 PM, said:

Bridgemates & duplicated boards make it feasible to use Bowman movements, so that you can have two more tables than boardsets.

Are scoring problems and unavailability of boards the main reasons for avoiding complex movements? I'd have thought that a bigger factor would be the risk that someone will do something stupid.

[Gerardo]

What is the Greek method?

[gordontd]

gnasher, on May 16 2010, 11:54 PM, said:

gordontd, on May 16 2010, 08:40 PM, said:

Bridgemates & duplicated boards make it feasible to use Bowman movements, so that you can have two more tables than boardsets.

Are scoring problems and unavailability of boards the main reasons for avoiding complex movements? I'd have thought that a bigger factor would be the risk that someone will do something stupid.

Bridgemates also help ensure that people play the correct boards at the correct time. But sharing two-board rounds is quite impractical without two sets of boards, and so is scoring the shared rounds in the correct place on a traveller.

[gordontd]

helene_t, on May 16 2010, 09:39 PM, said:

XIMPs is fine but IMHO it doesn't matter much whether you use XIMPs or matchpoints.

It matters in that the game is quite different.

[JoAnneM]

CSGibson, on May 14 2010, 07:20 AM, said:

Hi. I'm on my unit board, and we're thinking about having a two session cross imp pairs event for one of our sectionals this year. Any thoughts on that style of scoring, and it's appropriateness for the club level (which are the majority of players who would come out)?

Chris, congratulations on your GNT win yesterday!!! Good luck in New Orleans!

Jo Anne

(Sorry off-topic)

[CSGibson]

JoAnneM, on May 17 2010, 08:34 AM, said:

CSGibson, on May 14 2010, 07:20 AM, said:

Hi.  I'm on my unit board, and we're thinking about having a two session cross imp pairs event for one of our sectionals this year.  Any thoughts on that style of scoring, and it's appropriateness for the club level (which are the majority of players who would come out)?

Chris, congratulations on your GNT win yesterday!!! Good luck in New Orleans!

Jo Anne

(Sorry off-topic)

Thanks Joanne. We'll try and do district 20 proud.

[McBruce]

In our Unit, we run two single-session IMP Pairs games out of four sectionals a year, both on Friday evenings as the companion game to the first session of a three-round KO. I run the occasional IMP Pairs game in the Wednesday evening games that I run at the club. Scoring such a game is simple in ACBLScore -- set up the game normally, then type SET and choose option 9 (Change Scoring Method) and then choose option 3 (Average IMPs). The machine will prompt for a Maximum IMPs Swing with a default value of 24, which is fine -- you might choose something smaller to reduce the effect of freak hands, but in practice I seldom see more than one or two swings of 14 or more in a game.

It's my impression that IMP Pairs is far more popular than matchpoints in the main bridge club on BBO, but I don't know why. Regulars at club games have played matchpoints all their lives except for the occasional Swiss Teams and will be unfamiliar with a scoresheet where zero is average, so some announcement should be made at the start of the game about the scoring system when everyone is listening. I usually remind people that big scores will affect your result much more than in matchpoints, and that team game strategies apply rather than matchpoint strategies. But overall it is still just bridge, and frequently at the club I discover that the winning pair has not heard the announcement and thought they were playing matchpoints.

I'm not sure it is any more or less important to select any specific movement in IMP Pairs. The argument that some boards are more swingy than others, so all pairs should play exactly the same boards seems a bit flawed to me. As in matchpoints, where the scores on a board average to 50%, the average of all scores in IMP Pairs average to zero. But it is always desirable to have pairs play mostly the same boards, and I suppose it would be better to avoid a 15-18 table Mitchell, where pairs play quite different sets of boards -- but that is also true for matchpoints.

One advice I would give would be to avoid it for two-sessions, or if you must make it a two-session event, make it a qualifying/final setup and not a playthrough. For some reason, players at the lower end of the table leave with a much more negative reaction to their score in IMP Pairs than in matchpoints. If you are third-last in a 26-table field with 37.6% in matchpoints, you will come back and try to play well in the second session and get an session award, or perhaps even make the Flight C overalls with a big second session and some luck, and if you don't you'll just chalk the day up to bad luck. But if you leave for the dinner break with an IMP score of -97.62, somehow it feels like the worst game ever to most players and they will remember the experience and avoid IMP Pairs for the rest of their days. Setting the game up as a qualifying and final means that the pairs who did poorly in the first session can come back and start at zero in a consolation game in the second. It also makes your final session a much bigger test of skill and you will find that the final will contain most of your best players, as well as a few pairs who will mark it as a major achievement to have qualified for the final.

It does mean that you need to abandon stratification in the main event (you can stratify the consolation game). Our Unit runs a two-session unstratified matchpoints qualifying/final pairs game once a year and has discovered that adding a separate 0-750 game in the first session increases the overall attendance. Many players with 0-750 will avoid the big game without strats, but are content to join those in the stratified consolation game in the evening.

[barmar]

McBruce, on May 17 2010, 03:30 PM, said:

I'm not sure it is any more or less important to select any specific movement in IMP Pairs. The argument that some boards are more swingy than others, so all pairs should play exactly the same boards seems a bit flawed to me. As in matchpoints, where the scores on a board average to 50%, the average of all scores in IMP Pairs average to zero. But it is always desirable to have pairs play mostly the same boards, and I suppose it would be better to avoid a 15-18 table Mitchell, where pairs play quite different sets of boards -- but that is also true for matchpoints.

It's not the average that matters, it's the extremes.

In MP, a single board only contributes to 4% of your score. If you miss a board with a possible big swing, it can't hurt you too badly.

But in IMPs the contribution of each board varies significantly. Part-score boards generally only produce 1-5 XIMPS, while vulnerable games can produce 10 XIMPS, and slams even more.

If you play lots of boards, there should be enough boards of every type that it doesn't matter too much. But a 26-board session might only have 1 or 2 slammish hands. The pairs that bid and make those hands are at a significant advantage, it can make up for going down in a couple of part scores.

This is the same reason why Swiss Teams with short rounds and non-duplicated boards is unfair. If you get a set of boards with boring hands, you can't win (or lose) lots of IMPs.

[Vampyr]

Gerardo, on May 17 2010, 07:36 AM, said:

What is the Greek method?

The Greek method is just a way of converting an two-winner IMP game into a one-winner game. The top score is the winner, the top score from the other line comes in second, the 2nd place score from the first line comes in third, etc.

I think that this is a much fairer way than arrow-switching, because the arrow-switched boards have, potentially, too big an impact on one's score. I feel strongly that everyone in a particular line should have the same number of IMPs available to them -- at least in a 26-board event (see barmar's post).

But you think that arrow-switching is OK, Gerben42, and so, obviously do you, Gordon. I am prepared to admit that I am wrong, if you can explain your reasoning.

[Vampyr]

gordontd, on May 17 2010, 07:49 AM, said:

gnasher, on May 16 2010, 11:54 PM, said:

gordontd, on May 16 2010, 08:40 PM, said:

Bridgemates & duplicated boards make it feasible to use Bowman movements, so that you can have two more tables than boardsets.

Are scoring problems and unavailability of boards the main reasons for avoiding complex movements? I'd have thought that a bigger factor would be the risk that someone will do something stupid.

Bridgemates also help ensure that people play the correct boards at the correct time. But sharing two-board rounds is quite impractical without two sets of boards, and so is scoring the shared rounds in the correct place on a traveller.

But who uses travellers these days?

[Vampyr]

barmar, on May 18 2010, 07:52 AM, said:

This is the same reason why Swiss Teams with short rounds and non-duplicated boards is unfair. If you get a set of boards with boring hands, you can't win (or lose) lots of IMPs.

Sometimes resource constraints lead to Swiss teams with non-duplicated boards; I have seen this in Europe. But I would be surprised if any major event were played under these conditions.

[barmar]

Vampyr, on May 18 2010, 10:19 PM, said:

barmar, on May 18 2010, 07:52 AM, said:

This is the same reason why Swiss Teams with short rounds and non-duplicated boards is unfair. If you get a set of boards with boring hands, you can't win (or lose) lots of IMPs.

Sometimes resource constraints lead to Swiss teams with non-duplicated boards; I have seen this in Europe. But I would be surprised if any major event were played under these conditions.

In the US, duplicated Swiss teams is very rare. I've never heard of it in a sectional or regional tournament, but some of our local clubs do it. At nationals, I think only the finals of the national Swiss events use duplicated boards.

[gordontd]

Vampyr, on May 19 2010, 03:14 AM, said:

gordontd, on May 17 2010, 07:49 AM, said:

gnasher, on May 16 2010, 11:54 PM, said:

gordontd, on May 16 2010, 08:40 PM, said:

Bridgemates & duplicated boards make it feasible to use Bowman movements, so that you can have two more tables than boardsets.

Are scoring problems and unavailability of boards the main reasons for avoiding complex movements? I'd have thought that a bigger factor would be the risk that someone will do something stupid.

Bridgemates also help ensure that people play the correct boards at the correct time. But sharing two-board rounds is quite impractical without two sets of boards, and so is scoring the shared rounds in the correct place on a traveller.

But who uses travellers these days?

You seem not to have followed the sub-thread from its start. The point was that technology allows us to take advantage of more complex movements in order to minimise the number of surplus boards in a movement. You and I have had this conversation before.