Pairing players twice in a small Swiss

[nolan]

I don’t think there’s one rule that will work for everyone. It’s the job of the organizer and the TD to do what’s best for each specific situation, in most cases after consulting with the players.

Sometime it may make more sense to have some players face opponents more than once than to have them face players with large ratings differentials (which is often the case when pairing high score groups against much lower score groups.)

Keep in mind that the ratings formulas DO NOT CARE why players were paired against specific opponents, all they care about is trying to use those results to produce accurate ratings. The limitations on match rules exist because those tend to work against the goal of producing accurate ratings, and because we have a long history of attempts to manipulate the ratings system via matches.

[Smith]

@wintdoan

@jwiewel

In the 2017 non-rated standard Swiss tournament below (14 active players and 11 rounds) WinTD opted to have a rematch in the eighth round (1@7-0 vs 2@6-1) instead of dropping the 7-0 down two more scoregroups against the bottom 4-3. There was another rematch in round 11 with 1@10-0 vs 3@7-3 instead of dropping the 10-0 down three more scoregroups against one of the 4-6 players tied for 10-13.
The 11-0 ended up playing the 9-2 twice, one 7-4 twice, and once against the other 7-4, both 6-5 players and four of the five 5-6 players. I guess the remaining 5-6 and one of the 4-7 players would have been possible opponents.
The 7-4 player with no rematch played the 11-0, the 9-2, the other 7-4, both 6-5s, three of the five 5-6s, both 4-7s and the 1-10.
The 1-10 player had a bye and played one 7-4 and all at 6-5 or less.

If you crank the effort level up enough, it will find pairings without duplication. (In Round 11, pairing you with a 4-6, a 5-5 playing a 1-9, etc.)

What effort level do you recommend?

[jwiewel]

@Smith

@wintdoan

@jwiewel

In the 2017 non-rated standard Swiss tournament below (14 active players and 11 rounds) WinTD opted to have a rematch in the eighth round (1@7-0 vs 2@6-1) instead of dropping the 7-0 down two more scoregroups against the bottom 4-3. There was another rematch in round 11 with 1@10-0 vs 3@7-3 instead of dropping the 10-0 down three more scoregroups against one of the 4-6 players tied for 10-13.
The 11-0 ended up playing the 9-2 twice, one 7-4 twice, and once against the other 7-4, both 6-5 players and four of the five 5-6 players. I guess the remaining 5-6 and one of the 4-7 players would have been possible opponents.
The 7-4 player with no rematch played the 11-0, the 9-2, the other 7-4, both 6-5s, three of the five 5-6s, both 4-7s and the 1-10.
The 1-10 player had a bye and played one 7-4 and all at 6-5 or less.

If you crank the effort level up enough, it will find pairings without duplication. (In Round 11, pairing you with a 4-6, a 5-5 playing a 1-9, etc.)

What effort level do you recommend?

When computers were slower a lot of people used an effort level of 5, but I was fairly fast with entry and had a decent printer so I wasn’t bothered by the extra time used with an effort level of 50. As computers get faster and faster, increasing the effort level doesn’t really add much for time. I don’t know how much of a difference there is between 50 and much higher numbers.

I don’t remember the specific effort level in that non-rated blitz tournament but I was expecting that it would eventually reach the point where rematches simply could not be avoided because I hadn’t tried to make it a round-robin directed Swiss. We had a fixed finishing time rather than a fixed number of rounds and the rounds were going quicker than anticipated.

[BIRDSNAN]

@tmagchesspgh

Pairing two players again in a Swiss System event is a big violation of the pairing fundamentals. It is not a problem a TD should face in a large event with 6 or 7 rounds. There are always ways to make a pairing, even if it means going to other score groups. In smaller tournaments, you may run into the problem of not being able to make any legal pairing in a round, but that is the only reason I can think of for pairing players twice.

Rule 29 has many contradictory priorities and ambiguities. It leads to a wide variance in pairing styles, often based on how color conscious you are. Sometimes it is better to bring up a player from a lower score group than drop a player into a lower score group. The player brought up may have been part of an upset in an earlier round. Occasionally, you have to pair the bottom groups at the same time you are working on the top groups to make the pairings as fair as possible to all rather than cascade the pairing from top to bottom creating funkier pairings for the lower score groups.

I have run/assisted in 4 rd swisses with 6 players. You do the best you can. I’ve also been in a situation where the only legal pairing was an expert vs. a 900. I vetoed it.

Wasn’t there an FIDE Grand Prix…18 player 9 round swiss? What was done?

[wintdoan]

@BIRDSMAN

@tmagchesspgh

Pairing two players again in a Swiss System event is a big violation of the pairing fundamentals. It is not a problem a TD should face in a large event with 6 or 7 rounds. There are always ways to make a pairing, even if it means going to other score groups. In smaller tournaments, you may run into the problem of not being able to make any legal pairing in a round, but that is the only reason I can think of for pairing players twice.

Rule 29 has many contradictory priorities and ambiguities. It leads to a wide variance in pairing styles, often based on how color conscious you are. Sometimes it is better to bring up a player from a lower score group than drop a player into a lower score group. The player brought up may have been part of an upset in an earlier round. Occasionally, you have to pair the bottom groups at the same time you are working on the top groups to make the pairings as fair as possible to all rather than cascade the pairing from top to bottom creating funkier pairings for the lower score groups.

I have run/assisted in 4 rd swisses with 6 players. You do the best you can. I’ve also been in a situation where the only legal pairing was an expert vs. a 900. I vetoed it.

Wasn’t there an FIDE Grand Prix…18 player 9 round swiss? What was done?

Unlike 6 players-4 rounds, with 18/9 there almost certainly will always be a legal pairing. Of course, you’ll be down to “pick a victim” pairings by around round seven, but if everyone is a world class GM, it’s hard to say that downfloating 2.5 points is going to be a mismatch.