Swiss Pairs

[Vampyr]

I think Swiss pairs are a fun sounding format, and I certainly enjoyed them online (MP or IMP, it doesn't really matter either can be the basis of swiss pairs).

 

In the ACBL there are three obvious problems:

 

1. They are unfamiliar.  So you are less likely to see them.

 

This is why the ACBL also don't hold multiple teams events. Why they play two-winner movements and magically come up with a single winner. Why most (if I am not mistaken) clubs use hand-dealt cards and don't provide hand records. The "not invented here" syndrome is rather prevalent in North America.

 

2. They require pre-duplicated board sets to play more or less barometer style.  This should be done for all events IMO (for fairness and event integrity - certainly more important than cell phone bans), but it is a problem for organizers in the ACBL tradition.

 

This is true; you need about 1/(number of boards per round/2) the number of sets of boards as you have tables, for either Swiss pairs or Swiss teams. At the Brighton congress this requires someone to be working almost full-time between the two weekends preparing the boards. Do the ACBL not have the manpower? They don't even offer prizes at most events; surely they could afford people to prepare the hands.

 

3. I've heard the master point awards are off in that the master point awards are based on number of tables more so than number of players so you will not award as many points in a 400 person swiss pair than you do for a 400 person swiss team.  This is problematic if your goal as event organizer is to maximize the number of master points that are awarded.

 

Who awards the masterponts -- the ACBL? So... do they not have the power to create the masterpoint formulae?

 

I think that it would be incredibly dreary to have to play most of my bridge in the ACBL, especially as "bracketed knockouts" have become so prevalent. And I don't understand the appeal (except for the apparently inflated number of masterpoints awarded). Most people I know would not show up to an event if they were not guaranteed to be able to enter the top flight.

 

 

But really, I think it is good that different locations are offering different events.

 

In terms of making swiss teams more fair and accounting for SoS, that's what the ?Zeligmo? (I forget the spelling) method does where it uses the swiss results recorded to then "simulate" what would happen if a complete round robin were to be played.  The results of that calculated full round robin are then used to compare the team.  I'm sure someone here remembers the article in question which studied one of the big European team competitions.

People will be less likely to want to play if the results are not immediate and transparent to the players. Surely having people motivated to come to play is more important than deciding which is the "best" of the four top teams who showed up.

[McBruce]

I run a Swiss Pairs at the ACBL club I direct about once every two months. a short 2.5 hour mid-week evening game where we normally play 20-21 boards. This allows a five-round Swiss Pairs with four-board rounds, and without a dealing machine I spend about three hours pre-duplicaing 5 sets, which is enough for about 10-12 tables, our usual turnout.

 

ACBLScore awards the same overalls as for a club game for this event, plus reasonable match awards. Usually 95+% of the pairs win some points, and with the match awards added there are usually more points paid out in total. You do need to use software dedicated to Swiss Pairs and transfer only the final results to ACBLScore.

 

The key is in instructing players at the start. They need to know that:

--basic scoring is in matchpoints, so pairs strategies apply

--everyone is playing the same boards at once, with multiple copies of the same board around the room (so no loud comments)

--it's vital to pass boards down one table immediately once you have completed them and scored the result

--your matchpoint score in each round is converted to VPs in such a way that you need about 66% in a round to score a 20-0 blitz

--after round one, pairs are given new opponents based on their position in the standings

 

Players do enjoy the format, especially the feedback they get in later rounds by moving to a lower numbered table after a win. Even players who insist on a North-South or a stationary table at teams seem to enjoy the variety and excitement of vying for the right to play at "table 1."

 

Of course, after the first round, once play begins, you announce that even if you don't place in the overall awards, the winning pair in each match gets a match award.

 

 

As for the weaknesses of Swiss events in general, I think players tend to overestimate the difference between leaders and challengers. If you have the lead in a Swiss Teams event and play the 2nd place team, you're probably 3-8 VPs ahead of the 3rd vs 4th match. Your expectation in VPs, compared to the next few teams down the line, is probably negative. but your average expected VP result is probably 12-8 while 3rd vs 4th is maybe about 13-7: a difference of only one VP.

[Cascade]

What is the advantage in playing Swiss Pairs in converting scores to VPs?

 

I am particularly interested in MP scoring compared with carrying through the raw matchpoint score or percentage.

[gordontd]

What is the advantage in playing Swiss Pairs in converting scores to VPs?

 

I am particularly interested in MP scoring compared with carrying through the raw matchpoint score or percentage.

If you score in matchpoints or %, every board carries equal weight as in other matchpoint events. That sounds like a desirable thing in a matchpoint event, but the problem is that with fewer rounds, and longer ones than is usual in other matchpoint events, it's possible to have a very good or very poor match and for this to have a disproportionate effect on your final score.

 

This is especially so in the early rounds when strong pairs can meet very weak pairs. I once started a Swiss Pairs playing against a pair who it turned out had never played in anything other than an occasional club duplicate before, and we scored 94% on our seven-board match. I'm happy we only got 20 VPs for that.

 

Having said that, I've played in and run both sorts of events (when Bridgemates were first introduced the only software that scored Swiss Pairs didn't convert to VPs), and I think there are advantages and disadvantages to each.

[Finch]

I think that it would be incredibly dreary to have to play most of my bridge in the ACBL, especially as "bracketed knockouts" have become so prevalent. And I don't understand the appeal (except for the apparently inflated number of masterpoints awarded). Most people I know would not show up to an event if they were not guaranteed to be able to enter the top flight.

You need to remember that there have to be events in which the little guys can enjoy themselves and hope to win, or there will be no events at all.

[nige1]

Over the last 10 years or so imp-scored swiss pairs has become the overwhelmingly most popular form of two-session pairs event in Australia with many, if not most, congresses (two day red-point bridge event typically with pairs on Saturday and teams on Sunday) ditching the traditional matchpoints pairs event for imp-scored swiss pairs.

This format, where you are still matchpointing across the field, I haven't seen before; but it might appeal to players who still want to risk their contracts for overtricks and play in anti-percentage NT contracts.

Match-pointed pairs or board-a-match teams require different skills from imped pairs and and teams. In the former, each board has roughly the same weight, and an extra overtrick or undertrick may be crucial, inflating the skill factor.

 

A Swiss competition is a good compromise between a Knockout and a Round-robin. If you only have time to play a fixed number of boards, and you are choosing between these three formats, then Swiss is best. Results of Swiss competitions correlate best with "God's order".

[blackshoe]

Results of Swiss competitions correlate best with "God's order".

Who? What?

[Siegmund]

Aaaah! We have a Loki worshipper in our midst.

[Vampyr]

I think that it would be incredibly dreary to have to play most of my bridge in the ACBL, especially as "bracketed knockouts" have become so prevalent. And I don't understand the appeal (except for the apparently inflated number of masterpoints awarded). Most people I know would not show up to an event if they were not guaranteed to be able to enter the top flight.

You need to remember that there have to be events in which the little guys can enjoy themselves and hope to win, or there will be no events at all.

Well, I can scarcely argue with that! But I think that this is a little different, because people are entering an event that they have no chance of winning, no matter how well they do. That's why I don't understand the popularity of such events.

[TimG]

I think that it would be incredibly dreary to have to play most of my bridge in the ACBL, especially as "bracketed knockouts" have become so prevalent. And I don't understand the appeal (except for the apparently inflated number of masterpoints awarded). Most people I know would not show up to an event if they were not guaranteed to be able to enter the top flight.

You need to remember that there have to be events in which the little guys can enjoy themselves and hope to win, or there will be no events at all.

Well, I can scarcely argue with that! But I think that this is a little different, because people are entering an event that they have no chance of winning, no matter how well they do. That's why I don't understand the popularity of such events.

I'm not sure whether you're talking about entering an open event that they have no chance of winning or entering a bracketed/flighted event which, because they are in a non-top bracket/flight, they have no chance of winning the whole thing.

 

But, either way I can understand why the events might be popular. In an open event, people can compare their result to how they expected to do, they get to play against a few good (or great) opponents along the way which is a draw for some, and they get token awards (match or section awards) along the way.

 

In a bracketed/flighted event, there is the chance to win the bracket/flight in which they are entered. And, you still get the token awards along the way. People choose to play games against less than great players all the time.

 

Do not discount the social aspect of either event.

[awm]

All of these events have different advantages and disadvantages. For example:

 

Bracketed knockouts

Pros: You get to play long matches, which reduces the inherent randomness of IMP events. If the bracketing is reasonably accurate then you get to play against teams of comparable level, meaning that you will be challenged but you also have a chance to win. You can play essentially at your own pace, rather than having tightly clocked rounds as in a pairs game. If at some point you're out of contention you can quit the event (in fact, this will be done for you).

Cons: It's hard to "play up" which can be a good experience. This also reduces the ability of mediocre players to encounter world champions at the table (one of the things supposedly great about bridge). If the bracketing is inaccurate it can be frustrating for people who are placed in the wrong field.

 

Swiss events

Pros: You're not forced into a bracket and get to potentially play against everyone. However, you still get to play a reasonable percentage of matches against teams of comparable level (assuming teams perform as their level would imply). A lot of teams will be within striking distance of winning the event even in late rounds, so you almost always have a "chance to win" (or at least place in the overalls) until near the end if you can just blitz your last couple matches.

Cons: With lots of short matches, the event can be fairly random, even worse if using shuffled boards for swiss teams like in ACBL. There is a fair amount of luck in the draw as well, because different teams will play against very different strength of field. The ability of teams to stay within striking distance can also be frustrating, as a team which is leading going into the last round can beat a tough opponent by a small margin and still end up in second or third.

 

Pairs movement events

Pros: You get to play against almost everyone in the event, which is fun and equalizes strength of field. The event is less random than many other formats of comparable length (especially with matchpoint scoring). You're playing the same boards as everyone else, which also reduces the luck factor compared to swiss or even knockout events with shuffled boards.

Cons: You have to play against almost everyone in the event, including pairs which are much worse or much better than you are. If the field includes a lot of weak pairs, the event often degenerates into "who can best beat down the bad players" which is not exactly luck but arguably not a true test of bridge skill either. The timed aspect can be annoying, since everyone must be kept synchronized there is often a lot of waiting between rounds for the fast pairs (and a lot of "hurry up" from the director for the slow pairs).

[awm]

Perhaps another interesting observation is that swiss teams tend to favor pro teams.

 

Say you have a team of six, and your team is fairly average when the sponsor plays but one of the best teams when he sits out. Because of the way swiss is structured, if you play the sponsor for the first half of the matches you will not fall too far behind the leaders, since once you are behind you play a weaker strength of opposition.

 

Then for the second half, you're behind but not too far back, and you're playing a relatively weak opponent with your best lineup. Blitz them and you're back among the contenders (most of whom were playing stronger opposition).

 

In comparison, for a round robin event your score is more correlated to the "average strength" of your team rather than to the "strength of your team for a small number of critical matches at the end." A team that is weaker than the four-pros lineup but stronger than the pro team "on average" will probably finish ahead.

[nige1]

Aaaah! We have a Loki worshipper in our midst.

God's order: a perfect seeding order. I was trying to avoid quibbles about anomalies like "Team A usually beats Team B usually beats Team C usually beats Team A". Unfortunately I triggered the usual put-downs. Sorry.

 

Suppose 64 teams enter a competition and each team has time to play about 65 boards. Among the organizer's options are:

• 
   
  
• Round-robin: 63 x 1-board matches between each pair of teams. Lots of comparisons but they seem too short.
   
  
• Knockout: 6 x 11-board knock-out rounds, sending half the field home at each stage. Even were there no luck involved, the second best team could be eliminated on the first round.
   
  
• Double-elimination is a Knock-out, where you must be defeated twice to be eliminated. Many players think these are fairer than straight Knock-outs.
   
  
• Swiss: 8 x 8-board rounds. A gradual sieve with twice as many comparisons as a knockout.
   
  

A Swiss takes the Double-elimination idea to its logical conclusion. Hence, IMO, in typical circumstances, with limited time available, a Swiss is more effective than a knock-out or round-robin. This argument applies to both teams and pairs competition. I concede, that if you have unlimited time, a round-robin might be better.

 

A simulation might convince me that I'm wrong.

You need to remember that there have to be events in which the little guys can enjoy themselves and hope to win, or there will be no events at all.

We do enjoy Swiss competition, even when we don't win.

[phil_20686]

Actually I really like swiss pairs events. They have a number of advantages.

 

1) If you have a bad session you are not necessarily out of the running. As a junior with a fairly demainding phd and no car the comination of being tired on a friday evening, or being hunover for at least one morning, pretty much insures that I will have a bad session. Thus for national pairs events that are part social event and part serious bridge swiss makes a happy comprimise.

 

2)In a swiss pairs it is neither necessary nor desirable to score the MP scores across teh whole field. In brighton they run a 14 round swiss pairs with 7 (or is it eight?) board matches, but they score it by room, so in the top 25 tables you are only scoring up vs the other top 25 tables. This is one of the huge plus factors. This somewhat compensates for the huge plus factor you normally get from holding the points and declaring in whole field events.

 

3)Getting to play long(ish) matches against top pairs is really what bridge is all about.

 

4)The randomness argument doesnt really seem to hold up that much. As long as you keep playing well you will keep grinding out a reasonable number of VP's per match. Its true that on a given set of boards a good pair playing against you might just do the right thing and give you a bad score, but thats just bridge. It happens in every form of scoring.