BBO Discussion Forums: Swiss Pairs mis-matches - BBO Discussion Forums

Jump to content

  • 3 Pages +
  • 1
  • 2
  • 3
  • You cannot start a new topic
  • You cannot reply to this topic

Swiss Pairs mis-matches Question for Sven Pran

#1 User is offline   gordontd 

  • PipPipPipPipPipPipPip
  • Group: Advanced Members
  • Posts: 4,485
  • Joined: 2009-July-14
  • Gender:Male
  • Location:London

Posted 2015-January-22, 05:43

Here in the EBU we have regulations to deal with the situation where a pair has been assigned to the wrong opponents, usually as a consequence of them having entered their scores incorrectly, or of having played the match in the wrong polarity, and it not having been noticed in time. These regulations, contained in section 3.5 of our White Book, aim to compensate a pair who, through no fault of their own, play a match against a higher-ranking pair than they should, as well as to remove some benefit from a pair at fault who play a match against a lower-ranking pair.

These regulations work fine, but they are based on match-points being converted to Victory Points, our standard method here. Recently we have run a Swiss Pairs, and intend to repeat it, that is scored by match-points and not converted. What I wonder is whether Norway (or indeed anywhere else), as somewhere with lots of experience of running events of this type, has any regulations or methods for dealing with mis-matches?
Gordon Rainsford
London UK
0

#2 User is offline   Vampyr 

  • PipPipPipPipPipPipPipPipPipPip
  • Group: Advanced Members
  • Posts: 10,611
  • Joined: 2009-September-15
  • Gender:Female
  • Location:London

Posted 2015-January-22, 09:58

View Postgordontd, on 2015-January-22, 05:43, said:

Recently we have run a Swiss Pairs, and intend to repeat it, that is scored by match-points and not converted.


Please don't repeat it very often.
I know not with what weapons World War III will be fought, but World War IV will be fought with sticks and stones -- Albert Einstein
0

#3 User is offline   pran 

  • PipPipPipPipPipPipPipPip
  • Group: Advanced Members
  • Posts: 5,344
  • Joined: 2009-September-14
  • Location:Ski, Norway

Posted 2015-January-22, 10:55

View Postgordontd, on 2015-January-22, 05:43, said:

Here in the EBU we have regulations to deal with the situation where a pair has been assigned to the wrong opponents, usually as a consequence of them having entered their scores incorrectly, or of having played the match in the wrong polarity, and it not having been noticed in time. These regulations, contained in section 3.5 of our White Book, aim to compensate a pair who, through no fault of their own, play a match against a higher-ranking pair than they should, as well as to remove some benefit from a pair at fault who play a match against a lower-ranking pair.

These regulations work fine, but they are based on match-points being converted to Victory Points, our standard method here. Recently we have run a Swiss Pairs, and intend to repeat it, that is scored by match-points and not converted. What I wonder is whether Norway (or indeed anywhere else), as somewhere with lots of experience of running events of this type, has any regulations or methods for dealing with mis-matches?

No, we don't bother.

Our experience is that some few "mismatches" will not have any significant impact on the final ranking.

The top "N" pairs where "N" is the number of rounds played (and not exceeding 40% of the number of pairs) will usually be "correctly" ranked in the end regardless of such mismatches.
1

#4 User is offline   mycroft 

  • Secretary Bird
  • PipPipPipPipPipPipPipPip
  • Group: Advanced Members
  • Posts: 7,059
  • Joined: 2003-July-12
  • Gender:Male
  • Location:Calgary, D18; Chapala, D16

Posted 2015-January-22, 11:16

I have to admit, I've never understood "MPs converted to VPs" for Swiss Pairs. We don't do that for a straight matchpoint night, and unlike IMPs (where we are concerned about flattening out the huge swings), matchpoints are "same top on every board".

What is the benefit of limiting blitzing in 6 board rounds that is different from the 2, 3, or 4 board rounds?
When I go to sea, don't fear for me, Fear For The Storm -- Birdie and the Swansong (tSCoSI)
0

#5 User is offline   Vampyr 

  • PipPipPipPipPipPipPipPipPipPip
  • Group: Advanced Members
  • Posts: 10,611
  • Joined: 2009-September-15
  • Gender:Female
  • Location:London

Posted 2015-January-22, 12:20

View Postmycroft, on 2015-January-22, 11:16, said:

I have to admit, I've never understood "MPs converted to VPs" for Swiss Pairs. We don't do that for a straight matchpoint night, and unlike IMPs (where we are concerned about flattening out the huge swings), matchpoints are "same top on every board".

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


Not converting to VPs removes the whole "match" element of the event. In a match the boards are finished and you start afresh. If you just use matchpoints, one or two very good or very bad rounds could determine where you finish in the event.

Not too dissimilar to straight matchpoint events (especially as, if you are comparing to Swiss Pairs, you are talking about 7 or 8 boards per match). Why have two different events be so similar? There are plenty of each on the calendar.

An otherwise ordinary pairs event where each round you are matched up with opponents on a similar score score seems unappealing to me. Why is this being tried in the EBU, Gordon?
I know not with what weapons World War III will be fought, but World War IV will be fought with sticks and stones -- Albert Einstein
1

#6 User is offline   FrancesHinden 

  • Limit bidder
  • PipPipPipPipPipPipPipPipPip
  • Group: Advanced Members
  • Posts: 8,482
  • Joined: 2004-November-02
  • Gender:Female
  • Location:England
  • Interests:Bridge, classical music, skiing... but I spend more time earning a living than doing any of those

Posted 2015-January-22, 14:50

View PostVampyr, on 2015-January-22, 09:58, said:

Please don't repeat it very often.


Please do. I much prefer it (with or without a cap on the number of MPs you can win in one match).
0

#7 User is offline   Vampyr 

  • PipPipPipPipPipPipPipPipPipPip
  • Group: Advanced Members
  • Posts: 10,611
  • Joined: 2009-September-15
  • Gender:Female
  • Location:London

Posted 2015-January-22, 18:40

View PostFrancesHinden, on 2015-January-22, 14:50, said:

Please do. I much prefer it (with or without a cap on the number of MPs you can win in one match).


Why do you prefer it, Frances?
I know not with what weapons World War III will be fought, but World War IV will be fought with sticks and stones -- Albert Einstein
0

#8 User is offline   gordontd 

  • PipPipPipPipPipPipPip
  • Group: Advanced Members
  • Posts: 4,485
  • Joined: 2009-July-14
  • Gender:Male
  • Location:London

Posted 2015-January-23, 02:45

View PostVampyr, on 2015-January-22, 12:20, said:

Not converting to VPs removes the whole "match" element of the event. In a match the boards are finished and you start afresh. If you just use matchpoints, one or two very good or very bad rounds could determine where you finish in the event.

That's why it's better to use it when the rounds are shorter and the event is longer. The effect is that each board has equal value.

View PostVampyr, on 2015-January-22, 12:20, said:

Not too dissimilar to straight matchpoint events (especially as, if you are comparing to Swiss Pairs, you are talking about 7 or 8 boards per match).

That doesn't follow at all. The event we ran had 12x4-board rounds.

View PostVampyr, on 2015-January-22, 12:20, said:

Why have two different events be so similar? There are plenty of each on the calendar.

An otherwise ordinary pairs event where each round you are matched up with opponents on a similar score score seems unappealing to me. Why is this being tried in the EBU, Gordon?

It was used as the qualifier for the Two-Stars Pairs at the Autumn Congress. The existing formula of two sessions of match-pointed pairs no longer seemed very exciting and gave those who were doing badly little to play for. Since we give master points for matches won in Swiss Pairs, everyone has something to play for, even if they have been doing badly. Swiss Pairs gives some of the advantages of barometer scoring without the limitations of all-play-all.
Gordon Rainsford
London UK
0

#9 User is offline   pran 

  • PipPipPipPipPipPipPipPip
  • Group: Advanced Members
  • Posts: 5,344
  • Joined: 2009-September-14
  • Location:Ski, Norway

Posted 2015-January-23, 03:01

View PostVampyr, on 2015-January-22, 12:20, said:

Not converting to VPs removes the whole "match" element of the event. In a match the boards are finished and you start afresh. If you just use matchpoints, one or two very good or very bad rounds could determine where you finish in the event.

Not too dissimilar to straight matchpoint events (especially as, if you are comparing to Swiss Pairs, you are talking about 7 or 8 boards per match). Why have two different events be so similar? There are plenty of each on the calendar.

An otherwise ordinary pairs event where each round you are matched up with opponents on a similar score score seems unappealing to me. Why is this being tried in the EBU, Gordon?

What is the "match" element in a Swiss for Pairs? (Or for that sake in any barometer style event for pairs)
0

#10 User is offline   gordontd 

  • PipPipPipPipPipPipPip
  • Group: Advanced Members
  • Posts: 4,485
  • Joined: 2009-July-14
  • Gender:Male
  • Location:London

Posted 2015-January-23, 03:49

View Postpran, on 2015-January-23, 03:01, said:

What is the "match" element in a Swiss for Pairs? (Or for that sake in any barometer style event for pairs)

It is that, when scores are converted to Victory Points, your actions towards then end of a match will be affected by how you think you have done earlier in the match.
Gordon Rainsford
London UK
0

#11 User is offline   campboy 

  • PipPipPipPipPipPip
  • Group: Advanced Members
  • Posts: 2,347
  • Joined: 2009-July-21

Posted 2015-January-23, 04:14

View Postmycroft, on 2015-January-22, 11:16, said:

I have to admit, I've never understood "MPs converted to VPs" for Swiss Pairs. We don't do that for a straight matchpoint night, and unlike IMPs (where we are concerned about flattening out the huge swings), matchpoints are "same top on every board".

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

The benefit of limiting blitzing is that we don't want how much the top pairs beat weak pairs by to be a major factor in the final ranking of the top pairs. This is especially important if they will have played different weak pairs: how much we beat weak pair A by is at least a fair measure of something, but whether we beat weak pair A by more or less than you beat weak pair B by probably tells us more about the relative strengths of A and B than it does about ours.

In Swiss, pairs in contention to win won't be playing more than one or two weak pairs, and which weak pairs (if any) they play has a large amount of essentially random variability, most of which comes from the round 1 draw. In a normal pairs night, especially with a Howell or 3/4 Howell, this is less of an issue because you are much closer to comparing like with like.

[edited to change "teams" to "pairs" :)]
0

#12 User is offline   pran 

  • PipPipPipPipPipPipPipPip
  • Group: Advanced Members
  • Posts: 5,344
  • Joined: 2009-September-14
  • Location:Ski, Norway

Posted 2015-January-23, 06:17

View Postgordontd, on 2015-January-23, 03:49, said:

It is that, when scores are converted to Victory Points, your actions towards then end of a match will be affected by how you think you have done earlier in the match.

Am I right then that this has nothing to do with calculating MatchPoints from comparisons of scores or converting Matchpoints further on to Victory Points?

It is about the players being kept continuously updated on how they are currently ranked in the event. (A most valued feature of barometer type events.)
0

#13 User is offline   gordontd 

  • PipPipPipPipPipPipPip
  • Group: Advanced Members
  • Posts: 4,485
  • Joined: 2009-July-14
  • Gender:Male
  • Location:London

Posted 2015-January-23, 06:24

View Postpran, on 2015-January-23, 06:17, said:

Am I right then that this has nothing to do with calculating MatchPoints from comparisons of scores or converting Matchpoints further on to Victory Points?

It is about the players being kept continuously updated on how they are currently ranked in the event. (A most valued feature of barometer type events.)

If I understand what you are saying here, I don't think you understood what I was saying :)

If you play an eight-board match converted to VPs, if you think you have done very well on the first six boards you should play safe on the remaining two. If you think you have done very badly on the first six boards, you should take risks on the final two. Not all boards have equal value in a match.
Gordon Rainsford
London UK
0

#14 User is offline   StevenG 

  • PipPipPipPipPip
  • Group: Full Members
  • Posts: 626
  • Joined: 2009-July-10
  • Gender:Male
  • Location:Bedford, England

Posted 2015-January-23, 06:54

I don't really see the match element kicking in - after all, you don't get a bonus for winning the match (discounting master points awards), as the score just goes 9-11, 10-10, 11-9 etc.. If winning the match was important, why aren't positions determined by matches won, with VPs (or MPs) as the tiebreaker?
0

#15 User is offline   campboy 

  • PipPipPipPipPipPip
  • Group: Advanced Members
  • Posts: 2,347
  • Joined: 2009-July-21

Posted 2015-January-23, 07:44

View PostStevenG, on 2015-January-23, 06:54, said:

I don't really see the match element kicking in - after all, you don't get a bonus for winning the match (discounting master points awards), as the score just goes 9-11, 10-10, 11-9 etc.. If winning the match was important, why aren't positions determined by matches won, with VPs (or MPs) as the tiebreaker?

It's not just about winning the match, it's because the VP scale isn't linear. If you're a fair way behind, an average on the last board may get you 3VPs, a top 8VPs and a bottom 1VP. So the odds favour going for a top -- more than they would normally at any rate -- because you stand to gain much more than you stand to lose.
0

#16 User is offline   Vampyr 

  • PipPipPipPipPipPipPipPipPipPip
  • Group: Advanced Members
  • Posts: 10,611
  • Joined: 2009-September-15
  • Gender:Female
  • Location:London

Posted 2015-January-23, 08:20

View Postgordontd, on 2015-January-23, 06:24, said:

If I understand what you are saying here, I don't think you understood what I was saying :)

If you play an eight-board match converted to VPs, if you think you have done very well on the first six boards you should play safe on the remaining two. If you think you have done very badly on the first six boards, you should take risks on the final two. Not all boards have equal value in a match.


There is that, but also there is the fact that boards in past matches are finished and no longer have an effect on your score. Thiis is important always, but especially in the first match when the pairs may be mis-matched.

I appreciate the difference with a shorter match though. I don't mind if this other format replaces ordinary pairs and not Swiss Pairs!
I know not with what weapons World War III will be fought, but World War IV will be fought with sticks and stones -- Albert Einstein
0

#17 User is offline   pran 

  • PipPipPipPipPipPipPipPip
  • Group: Advanced Members
  • Posts: 5,344
  • Joined: 2009-September-14
  • Location:Ski, Norway

Posted 2015-January-23, 08:40

I am confused and cannot see that any of this discussion has any relevance at all in Swiss events for pairs, at least not the way we play Swiss pairs in Norway:

Immediately after each round (typically 3 or 4 Boards played simultaneously at all tables) each board in that round is scored out, resulting in a Match Point score in the range 0% - 100%.

The MP scores for each pair (accumulated over all the rounds played so far) is used when drawing the seating for the next, or more commonly the round following the next.

So for instance as soon as round 3 has been completed all pairs shift for round 4, and early during round 4 each pair receives a report with their results in round 3, their total number of matchpoints made so far, and instruction on where they shall be seated in round 5.

Is my confusion justified?
0

#18 User is offline   Vampyr 

  • PipPipPipPipPipPipPipPipPipPip
  • Group: Advanced Members
  • Posts: 10,611
  • Joined: 2009-September-15
  • Gender:Female
  • Location:London

Posted 2015-January-23, 08:53

View Postpran, on 2015-January-23, 08:40, said:

I am confused and cannot see that any of this discussion has any relevance at all in Swiss events for pairs, at least not the way we play Swiss pairs in Norway:

....

Is my confusion justified?


Yes, it is, if you thought the discussion was about the way things are done in Norway.
I know not with what weapons World War III will be fought, but World War IV will be fought with sticks and stones -- Albert Einstein
0

#19 User is offline   gordontd 

  • PipPipPipPipPipPipPip
  • Group: Advanced Members
  • Posts: 4,485
  • Joined: 2009-July-14
  • Gender:Male
  • Location:London

Posted 2015-January-23, 08:58

View PostVampyr, on 2015-January-23, 08:20, said:

There is that, but also there is the fact that boards in past matches are finished and no longer have an effect on your score.

I'm not surprised Sven is confused! What on earth do you mean by this?
Gordon Rainsford
London UK
0

#20 User is offline   Vampyr 

  • PipPipPipPipPipPipPipPipPipPip
  • Group: Advanced Members
  • Posts: 10,611
  • Joined: 2009-September-15
  • Gender:Female
  • Location:London

Posted 2015-January-23, 09:14

View Postgordontd, on 2015-January-23, 08:58, said:

I'm not surprised Sven is confused! What on earth do you mean by this?


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.
I know not with what weapons World War III will be fought, but World War IV will be fought with sticks and stones -- Albert Einstein
0

  • 3 Pages +
  • 1
  • 2
  • 3
  • You cannot start a new topic
  • You cannot reply to this topic

1 User(s) are reading this topic
0 members, 1 guests, 0 anonymous users