[TimG]

hrothgar, on Feb 16 2010, 08:35 AM, said:

With no SoS adjustment, tournament organizers need to run twelve 20 board rounds to have a 95% chance that the strongest team will place in any one of the top eight slots. (Simply put, Swiss Teams are a real crap shoot)

That study uses a field size of 128 teams and does not make any mention of the differences in skill levels of the top teams. Are the top 10 team nearly equal? Top 16? How much better than the field was the top team? How much better than the 2nd or 8th best teams?

It would be interesting to hear how often a non-top 10% team won the 128 team simulated Swiss. AWM has claimed that a mediocre team can win a Swiss with a good ("lucky") last round match.

The biggest Swiss event I could find in the last year's worth of New England regional results was 61 tables.

I've played in a lot of small Swisses (that's all there are in Maine). My sense, purely anecdotal, is that the winners are almost always one of the top teams in the event -- very rarely does a mediocre team (relative to the field) end up on top. However, a mediocre team having a good day, perhaps bolstered by an easy last round draw, will often sneak into the overalls.

[hrothgar]

Hi Tim

The field size for that study was based on the big Swiss Teams events that take place in the Gold Coast congress down in Oz. I agree that field size could have a significant impact on the results. With this said and done, this thread started out discussing Swiss Pairs. All other things being equal, I’d expect that the field size for a Swiss Pairs event would average about double that of a Swiss Teams.

As I recall, the study assumed that the strength of the field was normally distributed; however, it’s been a while since I played with this (I keep meaning to reimplement this all in MATLAB). In the mean time, you’ll probably need to direct specific questions to Gerben…

[TimG]

hrothgar, on Feb 16 2010, 11:04 AM, said:

The field size for that study was based on the big Swiss Teams events that take place in the Gold Coast congress down in Oz. I agree that field size could have a significant impact on the results. With this said and done, this thread started out discussing Swiss Pairs. All other things being equal, I’d expect that the field size for a Swiss Pairs event would average about double that of a Swiss Teams.

Swiss Pairs at an ACBL sectional, I believe. I would expect the field to be much smaller than the Gold Coast Congress, especially considering ACBL's propensity to flight events.

Perhaps Gerben is reading this thread...

[ArtK78]

Based on attendance at sectionals in our area, and including the fact that there will be single-session sectionally rated side games opposite the two-session Swiss Pairs, I would expect a turnout of between 10-20 tables for the Swiss Pairs.

[jdonn]

Despite that imps more random than mps and pairs more random than teams, I still don't find this form of scoring particularly random relative to what I want. Especially considering the inherent randomness in bridge anyway.

Besides there are other goals besides 'best team wins as much as possible'. For example the best players are probably most interested in playing the strongest opponents possible. The worst players are probably most interested in not getting creamed every round. The medium players probably enjoy a format where they have just a slight chance to win if the stars align. Even spectators, if there are any, are probably more interested in seeing very strong matchups decide the winner at the end of the event. So there is something for everyone in this format, aside from the fun since it essentially doesn't exist around these parts.

[jdonn]

TimG, on Feb 16 2010, 08:22 AM, said:

awm, on Feb 15 2010, 10:50 PM, said:

If the number one team plays the number two team in the last round, it is normally the case that if one team wins by a reasonable margin that team wins the event. However, the loser of the "number one versus number two" match usually finishes quite a ways down (i.e. not second or even third) with a weaker team (often one that played a much weaker strength of schedule) charging up the ladder into the 2nd or 3rd place spot. If the "number one versus number two" match results in a tie or near-tie then neither team will win the event and a mediocre team can charge into the lead by blitzing a mediocre opponent.

I doubt many mediocre teams win events this way. It also is good to remember that good teams sometimes have off days and teams somewhere between good and mediocre play well some days.

And I would add as a question, what makes the team in second with a round to go any more deserving of coming in second place if they lose the last round to the team in first than the team in third is if they win the last round against the team in fourth (by enough)? Would it be better if the team in second played the team in second to last and earned the victory only if they smashed them by more than the team in first smashed the team in last? I would barely even call that event bridge.

Btw you are assuming the field looks like this with a round to go:

1. Best team
2. Second best team
3. Mediocre team
4. Mediocre team
5. Mediocre team
....

Please tell me you see quite a few large problems with making those assumption...

[wank]

lol the swiss pairs at the english summer congress can get 250 tables in a good year. i don't know why it's not so popular in america.

i don't collect them myself but mugs love these events because the ebu awards a tiny fraction of a premium master point for every match won or drawn.

from what i've seen, americans love masterpoints even more than english mugs - i've seen amercans describe themselves as 1000 point players or whatever, whereas most people here have no idea what their masterpoint rank is, just that they want more points- if the acbl want to make these events more popular, crank out the masterpoint awards.

[gnasher]

Given the obsession with masterpoints amongst ordinary players in the ACBL, this format ought to be very popular.

[TimG]

gnasher, on Feb 16 2010, 01:08 PM, said:

Given the obsession with masterpoints amongst ordinary players in the ACBL, this format ought to be very popular.

It requires duplicated boards, doesn't it? The ACBL has been very slow to switch to machine duplicated boards; the last sectional I played in we hand duplicated boards and that was just a couple months ago.

In Swiss team events, the boards are typically hand shuffled and dealt prior to each match.

[mrdct]

TimG, on Feb 16 2010, 02:31 PM, said:

In Swiss team events, the boards are typically hand shuffled and dealt prior to each match.

It would be at least 20 years since I last saw a swiss teams event with hand shuffled boards.

[Siegmund]

There was one place that Swiss Pairs was commonly used in the US - in the "homestyle" games, non-duplicate games where you played 4-board matches against another pair and converted the result to VPs after each round.

They were a failed experiment to draw rubber bridge players into the club. They are still legal, and still award masterpoints at the usual club game rate, plus .06 per match won. They are somewhat less serious than the average game of Go Fish.

Myself, I would be delighted to never see a Swiss movement anywhere, pairs or teams, bridge or backgammon, for the rest of my life.

[MFA]

I like the format. It's cool that the pairs in contention battle it out face to face eventually. Of course one can't expect all pairs to finish in exact order of bridge skills, but that's the case in any short tournament. In swiss pairs it is not all just a competition in slaughtering the bad pairs the most.

Icelandair Open is a nice, annual tournament with this format.

[gnasher]

In Iceland and Norway they play a Swiss movement with 3- or 4-board rounds, whereas in England (and now Delaware) there are a smaller number of 8-board rounds.

One of BBO's competitors also used to run its pairs events on a Swiss basis, with two-board rounds. I don't know if they still do that.

There are advantages to both approaches: playing lots of short rounds means that by the end of the event all the pairs in contention will have played much the same set of opponents; long rounds increase the importance of the match between the two leading pairs on each round.

I think I prefer the Nordic style, as long as there are enough good pairs to go around. That might just be the novelty value, though.

[Vampyr]

mrdct, on Feb 16 2010, 09:05 PM, said:

TimG, on Feb 16 2010, 02:31 PM, said:

In Swiss team events, the boards are typically hand shuffled and dealt prior to each match.

It would be at least 20 years since I last saw a swiss teams event with hand shuffled boards.

In Europe, however, they are quite common. And they use Victory Points there as well. I have often wondered about the use of VPs in an event where the boards are hand-shuffled. My feeling is that the randomness added by the shuffled boards makes this inappropriate, and that win/loss should be used in such events. (The alternative would be a complicated VP scale involving factoring).

[WellSpyder]

jdonn, on Feb 16 2010, 11:41 AM, said:

Btw you are assuming the field looks like this with a round to go:

1. Best team
2. Second best team
3. Mediocre team
4. Mediocre team
5. Mediocre team
....

I know, let's just cancel the final round and then we will have teams in the desired order!

Slightly more seriously, I don't think the argument is that the teams WILL be in that order, just that it is the most likely order. But of course if that is the most likely order after n-1 rounds, it is also the most likely order after n rounds.

[TimG]

hrothgar, on Feb 16 2010, 08:35 AM, said:

With no SoS adjustment, tournament organizers need to run twelve 20 board rounds to have a 95% chance that the strongest team will place in any one of the top eight slots.  (Simply put, Swiss Teams are a real crap shoot)

Quote

With no SoS adjustment, tournament organizers need to run twelve 20
board rounds to have a 95% chance that the strongest team will place
in any one of the top eight slots. If we add an SoS adjustment,
tournament organizers can run nine 20 board rounds while still
achieving a 94.9% chance that the strongest team will place in any of
the top eight places. Tournament organizers can reduce the length of
the tournament by 25% without impacting the integrity of the results.
(In comparison, if the Tournament Organizers were to run an event with
nine 20 board rounds without any SoS adjustment, the accuracy of the
event would drop from 95% to 92.3%)

This doesn't sound to me like a crap shoot. At least not any more than most other forms of bridge. In a 64 table MP pairs, I wouldn't expect the best pair in the field to always be in the top 8; there are upsets every year in the Spingold and Vanderbilt.

[awm]

Here's an experiment which will perhaps illustrate the issue.

Take the results from a real swiss event (pairs, teams, whatever).

Consider two teams which finished close to each other in the standings. We probably only care about teams that finished close to the top, so consider two such teams (say 1st and 2nd place).

For each of these teams, we can compute the "strength of schedule" that they faced, in the simple way proposed. All this means is, you take all the opponents faced by each team and sum up their final victory points. To remove the effect of facing each other (if they did play each other) I suggest ignoring the teams in question. So:

For team one, compute the total of the final VPs of all teams they played except for team two.
For team two, compute the total of the final VPs of all teams they played except for team one.

My claim is that if team one has a substantially weaker strength of schedule according to this formulation, then something has gone wrong. The team that placed second can easily be a better team, yet they had to play against much stronger opposition and therefore couldn't rack up as many VPs.

I suggest that this situation (1st place team has substantially weaker schedule than 2nd place team) is not at all rare in a swiss event. This issue doesn't exist in "round robin" type formats.

With that said, I agree that sometimes "random events" are fun (they give more people the opportunity to win or place high) and there is some benefit to people getting to play teams of "comparable level" as much as possible. There is absolutely nothing wrong with running a swiss pairs and I'd probably play in one occasionally. Variety is certainly good.

On the other hand, I think there is a problem if events which are "less random" (i.e. more skill) are being consistently replaced with events which are "more random." I would not like to see all the MP pair events (or even a substantial majority) replaced by swiss IMP pairs (as seems to be the case in some regions).

[barmar]

Vampyr, on Feb 17 2010, 12:02 AM, said:

mrdct, on Feb 16 2010, 09:05 PM, said:

TimG, on Feb 16 2010, 02:31 PM, said:

In Swiss team events, the boards are typically hand shuffled and dealt prior to each match.

It would be at least 20 years since I last saw a swiss teams event with hand shuffled boards.

In Europe, however, they are quite common. And they use Victory Points there as well. I have often wondered about the use of VPs in an event where the boards are hand-shuffled. My feeling is that the randomness added by the shuffled boards makes this inappropriate, and that win/loss should be used in such events. (The alternative would be a complicated VP scale involving factoring).

It's also still common in the US.

There are some clubs that use preduplicated boards in Swiss teams (or small clubs that play a full round robin). But I've never seen them in tournaments. Maybe the final day of the North American Swiss at the NABC uses preduplicated boards.

[Vampyr]

awm, on Feb 17 2010, 11:55 PM, said:

I would not like to see all the MP pair events (or even a substantial majority) replaced by swiss IMP pairs (as seems to be the case in some regions).

I would not like to have any major pairs events to be changed to IMP pairs, whether Swiss or not.

I don't think that adjusting results based on some sort of "Swiss points" system is a good idea. For one thing, it seems that you would have to make the adjustment after every round instead of just at the end, so the scoring system would be opaque and not comprehensible to the players.

Another problem is that early in the event there will be many pairs on the same scores, so there will be a lot of randomness in whom you are drawn against, so the method seems rather unfair.

One year in the Brighton Swiss Teams, we started the Saturday morning with 10 VPs on a 30 average, because one of our team was a bit the worse for wear on the Friday evening. On Saturday we sliced through the field like a knife through butter, and ended up in the secondary final.

Would it have been "fairer" for us to miss out, since our Swiss points would not have been very many? Would it have made it a "better" event? What do these words mean?

[paulg]

MFA, on Feb 16 2010, 11:01 PM, said:

I like the format. It's cool that the pairs in contention battle it out face to face eventually. Of course one can't expect all pairs to finish in exact order of bridge skills, but that's the case in any short tournament. In swiss pairs it is not all just a competition in slaughtering the bad pairs the most.

Icelandair Open is a nice, annual tournament with this format.

The Icelandair, in common with one of the Scottish tournaments, does not convert a match to victory points but you keep your matchpoint score - barometer (swiss) pairs is a better description of this event.

I think it is a great format and better than Swiss Pairs converted to VPs.