[pran]

 Vampyr, on 2015-January-23, 09:14, said:

Well, I mean that you get your VPs and the boards no longer have an effect on your scores, for example, you can get a bottom on a board and still have a big win, even 20-0. You can have two bottoms and a big win. Or a tie or whatever. Without VPs, those 0% boards will drag your score down for the rest of the event.

Do you play Swiss pairs considering each round a separate and complete tournament on its own?

That is:
Here is the prize list for round 1
Here is the prize list for round 2
Here is the prize list for round 3
Here is the prize list for round 4
.....
And there is no prize list for the entire event consisting of say 15 rounds?

That is the only way I can see how the results in round 1, 2, 3 and so on have no effect on later rounds.

I am still confused.

PS.: And what scores are the base for assigning seats in for instance round 15?

[Mbodell]

 pran, on 2015-January-23, 10:05, said:

Do you play Swiss pairs considering each round a separate and complete tournament on its own?

That is:
Here is the prize list for round 1
Here is the prize list for round 2
Here is the prize list for round 3
Here is the prize list for round 4
.....
And there is no prize list for the entire event consisting of say 15 rounds?

That is the only way I can see how the results in round 1, 2, 3 and so on have no effect on later rounds.

I am still confused.

PS.: And what scores are the base for assigning seats in for instance round 15?

I don't see how this can be confusing. You play round 1. Everyone has MP scores for that round. You have a mapping from various MP cutoffs to various VP awards (for simplicity lets say 70+% => 20 VP; 66-70% => 19 VP; 62-66% => 18VP; 60-62% => 17 VP; 58-60% => 16 VP; 56-58% => 15 VP; 54-56% => 14 VP; 53-54% => 13 VP; 52-53% => 12 VP; 51-52% => 11 VP; 49-51% => 10 VP; and so on for the losing VP percentages - I made these up for illustrative purposes, there is a real scale depending on number of boards in the various CoC and regulations). Now you pair people based on their VP totals. In round 2, you score just the round 2 boards by MP. You then convert round 2's MP score to VP again. The MP in round 1 have no direct effect on the MP in round 2 or the VP earned in round 2 (but do effect the pairing - assuming you are doing current round pairings and not r-1 pairings). So just like you often pair swiss teams by VP totals, not IMP totals, and the IMP=>VP earned in round X is calculated without any reference to rounds X-1 and behind, so it is the same in swiss pairs with match scoring. At the end of the night the winning pair is the one with the most VP.

It makes much more sense to me to do the match scoring and VP than to just do raw match points through out the night.

[blackshoe]

 Mbodell, on 2015-January-23, 12:45, said:

It makes much more sense to me to do the match scoring and VP than to just do raw match points through out the night.

Are you saying that it makes more sense to VP each "match" as it happens rather than to VP at the end of the session, or are you saying that it makes more sense to VP the matches rather than just score on the basis of raw match points?

Either way, why?

[pran]

 Mbodell, on 2015-January-23, 12:45, said:

I don't see how this can be confusing. You play round 1. Everyone has MP scores for that round. You have a mapping from various MP cutoffs to various VP awards (for simplicity lets say 70+% => 20 VP; 66-70% => 19 VP; 62-66% => 18VP; 60-62% => 17 VP; 58-60% => 16 VP; 56-58% => 15 VP; 54-56% => 14 VP; 53-54% => 13 VP; 52-53% => 12 VP; 51-52% => 11 VP; 49-51% => 10 VP; and so on for the losing VP percentages - I made these up for illustrative purposes, there is a real scale depending on number of boards in the various CoC and regulations). Now you pair people based on their VP totals. In round 2, you score just the round 2 boards by MP. You then convert round 2's MP score to VP again. The MP in round 1 have no direct effect on the MP in round 2 or the VP earned in round 2 (but do effect the pairing - assuming you are doing current round pairings and not r-1 pairings). So just like you often pair swiss teams by VP totals, not IMP totals, and the IMP=>VP earned in round X is calculated without any reference to rounds X-1 and behind, so it is the same in swiss pairs with match scoring. At the end of the night the winning pair is the one with the most VP.

It makes much more sense to me to do the match scoring and VP than to just do raw match points through out the night.

I am at a loss on how anybody can state that the results in rounds 1, 2, 3 and so on has no impact on later rounds if Match Point scores were converted to VP scores so long as the outcome of the event is decided by the accumulated sum of whatever kind of scores won in all rounds during the entire event.

Anyway, our experience is that the final results based on Match Points calculated as specified in Law 78A extremely seldom extend outside the range 40% - 60%. So the alleged advantage by converting Match Points to Victory Points seems rather obscure to me.

[Vampyr]

 blackshoe, on 2015-January-23, 13:52, said:

Are you saying that it makes more sense to VP each "match" as it happens rather than to VP at the end of the session, or are you saying that it makes more sense to VP the matches rather than just score on the basis of raw match points?

Either way, why?

I would say both, and the reason for me is that it makes a more enjoyable event.

[Vampyr]

 pran, on 2015-January-23, 14:05, said:

I am at a loss on how anybody can state that the results in rounds 1, 2, 3 and so on has no impact on later rounds if Match Point scores were converted to VP scores so long as the outcome of the event is decided by the accumulated sum of whatever kind of scores won in all rounds during the entire event.

Maybe you saw what I wrote above which is that you get your victory points at the end of a match, but the boards are now completely finished, and your good or bad boards in a completed match will not affect your score anymore. Do you play Swiss Teams in Norway, and use VPs? It is like that. You can go for 1700 against nothing, but after the match in question this will not be part of your score for the event. And you may win the match as well.

When raw percentages are used in Swiss Pairs, does the concept of winning or losing a match exist?

[Vampyr]

 pran, on 2015-January-23, 14:05, said:

Anyway, our experience is that the final results based on Match Points calculated as specified in Law 78A extremely seldom extend outside the range 40% - 60%. So the alleged advantage by converting Match Points to Victory Points seems rather obscure to me.

I think you will find that in an eight-board match there is a greater range of scores.

[mycroft]

I still don't get it. If the boards are never played again, the 62% which becomes 18 VPs could be converted to 7.5 Final% (8 7-board matches) instead. "After the match the score will not affect anything ever again", again, no? Or the 38% that becomes 2 VPs became 4.5 Final% instead?

I can see an issue if your 55% on one board used for pairing turns into a 45% by the end of the night (or vice versa) - but that doesn't happen in Swiss Pairs, does it?

I understand Campboy's wish to limit the difference in the seeding rounds between 94% and 86% based on whether you got the truly horrible or merely the horrible in the two rounds before you're playing your kind of teams - and I can understand not discounting those rounds or the Swiss gambit will work even better - but I can't tell the difference between a matchpoint score that won't change after the round's over and a converted-to-VP score that won't change after the round's over - especially given that the potential value of the match is identical (which it isn't, even with duplicated boards, in an IMP event).

Obviously I'm missing something.

[Vampyr]

 mycroft, on 2015-January-23, 15:52, said:

I still don't get it. If the boards are never played again, the 62% which becomes 18 VPs could be converted to 7.5 Final% (8 7-board matches) instead. "After the match the score will not affect anything ever again", again, no? Or the 38% that becomes 2 VPs became 4.5 Final% instead?

I can see an issue if your 55% on one board used for pairing turns into a 45% by the end of the night (or vice versa) - but that doesn't happen in Swiss Pairs, does it?

I understand Campboy's wish to limit the difference in the seeding rounds between 94% and 86% based on whether you got the truly horrible or merely the horrible in the two rounds before you're playing your kind of teams - and I can understand not discounting those rounds or the Swiss gambit will work even better - but I can't tell the difference between a matchpoint score that won't change after the round's over and a converted-to-VP score that won't change after the round's over - especially given that the potential value of the match is identical (which it isn't, even with duplicated boards, in an IMP event).

Obviously I'm missing something.

Well, suppose you get a zero on one board, but still win the match 20-0. For example. So that zero has no effect at all on your score.

Edit: Campboy plays in a country where there is only one random pairing; one-round-in-arrears scoring was scrapped by the EBU years ago.

[pran]

I still don't understand what is meant by "match" in a barometer style event for pairs.

But I can obviously clarify some of the questions asked:

Yes, we have Swiss events for Teams as well, in one of mine the setup was:
20 teams (of four) met in 9 sessions playing one match (against one other team) each session. Each match consisted of two rounds with 12 Boards each, and in all matches the same 12 boards were played simultaneously during the same round. The scoring was standard IMP converted to VP.

For each session after the first the teams were seated as follows:
Table 1: The currently leading team against the best placed team they had not yet met
Table 2: Same procedure applied to the teams not yet seated
Table 3: Same procedure again - and so on.

I believe this is "standard procedure" for all Swiss teams competitions?

A similar preocedure is followed for our Swiss for Pairs events, but we have no such concept as "matches" there.

A typical setup is:

50 pairs* meet in 16 rounds playing 4 Boards in each round (the same boards simultaneously at all tables!). Seatings are allocated randomly for the first two rounds.
Scoring in each round is standard matchpoint scoring with scores on each board ranging from +49 to -49
For each round after the second the pairs are seated as follows:
Table 1: The currently leading pair (after the last round scored) against the best placed pair they have not yet met
Table 2: Same procedure applied to the pairs not yet seated
Table 3: Same procedure again - and so on.

So for instance during round 4 we have just scored out round 3 and determined the seatings in round 5. Result slips are now handed out to each pair so that they learn their current score and where to go for round 5.

* We have had events with more than 200 pairs, see for instance:
http://bridge.no/var.../2014mixpar.htm (213 pairs, 30 rounds, 3 boards/round)

[Vampyr]

 mycroft, on 2015-January-23, 15:52, said:

but I can't tell the difference between a matchpoint score that won't change after the round's over and a converted-to-VP score that won't change after the round's over - especially given that the potential value of the match is identical (which it isn't, even with duplicated boards, in an IMP event).

Obviously I'm missing something.

No, it is my very evident inability to explain it, but perhaps there is another way of looking at it.

Suppose Team A score 89% in their first match and Team B score 69%. They will both win their match 20-0 in terms of VPs, so they will be on the same score. If they are paired up in Match 2 it is as exact equals. (I don't know whether 69% is above the cutoff for 20VPs in a typical-length match, but obviously that detail is irrelevant).

[FrancesHinden]

 Vampyr, on 2015-January-23, 19:58, said:

No, it is my very evident inability to explain it, but perhaps there is another way of looking at it.

Suppose Team A score 89% in their first match and Team B score 69%. They will both win their match 20-0 in terms of VPs, so they will be on the same score. If they are paired up in Match 2 it is as exact equals. (I don't know whether 69% is above the cutoff for 20VPs in a typical-length match, but obviously that detail is irrelevant).

Yes. I don't understand why you think that is a good thing.

[gordontd]

 Vampyr, on 2015-January-23, 09:14, said:

Well, I mean that you get your VPs and the boards no longer have an effect on your scores, for example, you can get a bottom on a board and still have a big win, even 20-0. You can have two bottoms and a big win. Or a tie or whatever. Without VPs, those 0% boards will drag your score down for the rest of the event.

The boards contribute to the score for that round, and that score remains unchanged for the rest of the event (scoring corrections notwithstanding). That applies whether the score was in matchpoints, IMPs or VPs.

[gordontd]

 mycroft, on 2015-January-22, 11:16, said:

What is the benefit of limiting blitzing in 6 board rounds that is different from the 2, 3, or 4 board rounds?

You are going to play a much smaller proportion of the field and one round will have a much larger effect on your overall score. I once played a local Swiss Pairs where, although it was scored in VPs, the scoring program showed our percentage. On the first round we were drawn against a very inexperienced pair indeed and scored 94%. I think it was better that it was converted to VPs, since it would have been an unreasonable advantage to have be benefit of a 94% score for 1/7 of the event.

[Vampyr]

 FrancesHinden, on 2015-January-24, 12:03, said:

Yes. I don't understand why you think that is a good thing.

Well, Gordon's comment just above is part of the reason, also that since VPs are cumulative your score can go up or down by a lot, which is perhaps a bit of a randomiser, but I find they it makes the event more exciting.

I guess it is partly psychological, too; if I have a bad board but still get 18 or 20 VPs (or a well-deserved 0) from a match, then I can move on to the next match more easily. I don't have to try to, nor can I, overcome the effect of the poor board.

Also, and this is important, with VPs you are scored against the pair you are playing, with whom you are supposedly evenly matched. If you are continually scored across the whole field then I think that the Swiss effect is entirely lost.

I guess you don't like Swiss Teams with VPs either, but these are also widely offered in the EBU so my opinion of these events is probably more prevalent than yours. Maybe your point of view is shared by many of the top players like yourself, but these are not the bulk of the EBU members.

I do think, however, that the straight percentages method might be quite fun for a qualifier. As a main event, I really feel it lacks something.

[mycroft]

Okay, I think I understand now. I'm not sure I'm happy that 31% of the matchpoints is worth nothing, but I've always had issues with that in team games as well.

It looks like there's two different games, and they both would be interesting.

Thank you for the "help me understand" - it helped me understand.

Re: one round in arrears - I guessed that (I know nowhere where they do that, at least any more), but it still takes a couple of rounds before you've shaken out the field. In Australia where they (used to?) seed the first round 1 vs 51, 2 vs 52...50 vs 100, effectively round 2 was "random draw 1-50, and random draw 51-100" as the first matches were almost all killers. In our club game, we seed the field differently (A with A, B with B, round 1); so now round 2 is "which A team that won 15-5 gets the C team that won their C match 15-5, and which gets the other A team that won 16-4?") - there are a lot of blitzes round 2 for some reason. Even if it's totally random seeding round 1, there are 4 kinds of matches:

• evenly matched good teams
  
• evenly matched weaker teams
  
• mild mismatches
  
• killer mismatches

and there are a bunch of round 1 medium winners of even A matches that catch medium winners of C matches (and, of course, medium losers of even A matches who catch medium losers of C matches) which tend to bring in predictable results. After a couple of rounds, 3 at the most, things start to run as much to form as they're likely to.

[mycroft]

And sure enough, I look over last night at the next table, where The Round 2 Match featured two 19/20 VP teams: I know Masterpoints Mean Nothing™, but as I said to our table: "So, we have 28 thousand masterpoints vs... 28". Okay, I might have been understating for effect, but I know it was less than 80 for the team of 4, because the highest MP rating was 19.

I'll let you guess the result of that match :-)

[Vampyr]

 mycroft, on 2015-January-26, 15:15, said:

Okay, I think I understand now. I'm not sure I'm happy that 31% of the matchpoints is worth nothing, but I've always had issues with that in team games as well.

It looks like there's two different games, and they both would be interesting.

Thank you for the "help me understand" - it helped me understand.

Re: one round in arrears - I guessed that (I know nowhere where they do that, at least any more), but it still takes a couple of rounds before you've shaken out the field. In Australia where they (used to?) seed the first round 1 vs 51, 2 vs 52...50 vs 100, effectively round 2 was "random draw 1-50, and random draw 51-100" as the first matches were almost all killers. In our club game, we seed the field differently (A with A, B with B, round 1); so now round 2 is "which A team that won 15-5 gets the C team that won their C match 15-5, and which gets the other A team that won 16-4?") - there are a lot of blitzes round 2 for some reason. Even if it's totally random seeding round 1, there are 4 kinds of matches:

• evenly matched good teams
  
• evenly matched weaker teams
  
• mild mismatches
  
• killer mismatches

and there are a bunch of round 1 medium winners of even A matches that catch medium winners of C matches (and, of course, medium losers of even A matches who catch medium losers of C matches) which tend to bring in predictable results. After a couple of rounds, 3 at the most, things start to run as much to form as they're likely to.

Yeah, one round in arrears is rubbish. But anyway, I think that you might have better results if you didn't seed the field. We don't here and there don't seem to be huge mismatches in round 2. Or you could separate the different levels into their own fields. As far as the VPs go, well some people like them and some don't. There are plenty of events for both types of people.

Of course, there are places where VPs are used where the same boards are not played at all the tables, and I don't know if anyone likes these!

EDIT: By the way, when the points won are limited to 20, the team that lost 20-0 is still in the event.

[TimG]

Might it be the case that total MP is fine for events with short rounds but that VP is better for events with longer rounds?

Does anyone know of an online reference for Swiss Pair events? I've done some googling tonight, but can't find much of anything.

Most of the items I have found talk about pairing being staggered one round. Isn't this a thing of the past with the use of Bridge Mates?

[gordontd]

 TimG, on 2015-October-12, 20:30, said:

Might it be the case that total MP is fine for events with short rounds but that VP is better for events with longer rounds?

I think that's true. The advantage of total MP is that each board has equal value. In a match converted to VPs the later boards in the match will have greater or lesser value depending on how the match has gone thus far. The advantage of VPs is that a very mis-matched first round doesn't carry over a disproportionate effect.

 TimG, on 2015-October-12, 20:30, said:

Does anyone know of an online reference for Swiss Pair events? I've done some googling tonight, but can't find much of anything.

Did you find the basic articles on David Stevenson's website?

 TimG, on 2015-October-12, 20:30, said:

Most of the items I have found talk about pairing being staggered one round. Isn't this a thing of the past with the use of Bridge Mates?

Yes, it has largely been supplanted by the use of Bridgemates.