All reports
#56504: "Swiss System repeatedly pairs the top-ranked player against the bottom-ranked player"
What is this report about?
BGA website
What happened ? Please select from below
Something didn't function correctly while using the website (not during a game)
Detailed description
• Please copy/paste the error message you see on your screen, if any.
not applicable• Please explains what you wanted to do, what you do and what happened
Please look at this tournament: boardgamearena.com/tournament?id=104287
It's "Swiss system" with "try to prevent same players to be opponents twice". I am Mathew5000 and have been at the top of the standings for almost the whole tournament. There's only 18 players (after 2 withdrew) and 20 matches.
For the last four matches of the tournament ("Step 17" through "Step 20") I was paired against Amelie1605 every time. That should not happen because "try to prevent same players to be opponents twice" is checked. But it especially should not happen because Amelie1605 is at the bottom of the standings while I am at the top of the standings; in Swiss System, I should be playing other players near the top of the standings, not the player at the bottom four times.
This is very unfair to the other players.• What is your browser?
irrelevant
Report history
5. Jan 2022 21:26 • Mathew5000 • Bug has not been reproduced by delopers yet:
Screenshots of pairings and standings: www.smugmug.com/gallery/n-KXMWsD/
5. Feb 2022 11:56 • mrdoctor • Bug has not been reproduced by delopers yet:
It seems like Swiss system tournaments make the matching algorithm go weird once it gets through one cycle of its normal attempt to not match people twice, and will then just match the same players multiple games in a row with no changing it up
20. Jan 2023 4:23 • Mathew5000 • Bug has not been reproduced by delopers yet:
Discussed in the Forums in December 2022 / January 2023 here:
boardgamearena.com/forum/viewtopic.php?t=28338
boardgamearena.com/forum/viewtopic.php?t=28338
5. Jun 2023 5:36 • BBT • Bug has not been reproduced by delopers yet:
boardgamearena.com/tournament?id=154738
Happened in rounds 14+ of this tournament
Happened in rounds 14+ of this tournament
4. Oct 2023 17:28 • Superluminal • Bug has not been reproduced by delopers yet:
I can attest to this issue. I am currently tied at the top of the leaderboard in a tournament that has been ongoing for over three months. This tournament features 3-player Tash-Kalar Deathmatch games. The pairing policy "Try to prevent the same players from being opponents twice" is activated for this event. Despite having played against each participant once, I've found myself repeatedly matched against the same players. My username is superluminal. You can verify the pairings here:
boardgamearena.com/tournament?id=184247
From games 12 to 16 (current game), I've been paired with one player 4 out of the 5 times. Another player has been my opponent in 3 out of these 5 games. Notably, both of these players are at the bottom of the leaderboard. I'm currently sharing the first place with rogernunn1. I fail to understand the logic of pairing players from the top of the leaderboard with those at the bottom, particularly towards the tail end of the tournament. This is the point where top contenders should ideally be pitted against one another to determine the final winner.
Rogernunn1 faces a similar issue. He's been matched with the same player for the fifth consecutive game, a player who seems to have abandoned the tournament and has not done any moves since a long time.
It's deeply frustrating to experience such irregularities, especially after dedicating so much time to a long tournament. I have been desperately waiting for a challenging match against rogernunn1, eager for a good fight. It's only logical that those at the top of the leaderboard should play against one another to determine the ultimate winner. Ideally, players like rogernunn1 and I should be paired, or at the very least, against others with high scores. I suspect that players at the lower end of the leaderboard aren't enjoying this any more than we are, continually finding themselves outmatched by the top contenders.
boardgamearena.com/tournament?id=184247
From games 12 to 16 (current game), I've been paired with one player 4 out of the 5 times. Another player has been my opponent in 3 out of these 5 games. Notably, both of these players are at the bottom of the leaderboard. I'm currently sharing the first place with rogernunn1. I fail to understand the logic of pairing players from the top of the leaderboard with those at the bottom, particularly towards the tail end of the tournament. This is the point where top contenders should ideally be pitted against one another to determine the final winner.
Rogernunn1 faces a similar issue. He's been matched with the same player for the fifth consecutive game, a player who seems to have abandoned the tournament and has not done any moves since a long time.
It's deeply frustrating to experience such irregularities, especially after dedicating so much time to a long tournament. I have been desperately waiting for a challenging match against rogernunn1, eager for a good fight. It's only logical that those at the top of the leaderboard should play against one another to determine the ultimate winner. Ideally, players like rogernunn1 and I should be paired, or at the very least, against others with high scores. I suspect that players at the lower end of the leaderboard aren't enjoying this any more than we are, continually finding themselves outmatched by the top contenders.
17. Oct 2023 10:33 • Arxij • Bug has not been reproduced by delopers yet:
Another example with the same issue /tournament?id=185083#stage_display
17. Oct 2023 10:34 • Arxij • Bug has not been reproduced by delopers yet:
*correct link boardgamearena.com/tournament?id=185083#stage_display
7. Jan 2024 16:39 • redeemedmonkeycma • Bug has not been reproduced by delopers yet:
Here's another example.
boardgamearena.com/tournament?id=249834
Top player matched with bottom 3 for rounds 8&9, and with two of them for rounds 6,7,8,9
Perhaps in the interim, you should caution people not to play more rounds of swiss than floor((total registered -1) / (# of opponents per game)). Or caution that there is a live bug with option ""Try to prevent the same players from being opponents twice"
boardgamearena.com/tournament?id=249834
Top player matched with bottom 3 for rounds 8&9, and with two of them for rounds 6,7,8,9
Perhaps in the interim, you should caution people not to play more rounds of swiss than floor((total registered -1) / (# of opponents per game)). Or caution that there is a live bug with option ""Try to prevent the same players from being opponents twice"
27. Dec 2024 19:08 • BananaHarambe • Bug has not been reproduced by delopers yet:
This is certainly a bug, but responsibility also falls under the tournament organizer for creating such an unconventional Swiss tournament with a high number of matches and very few players, a bad tournament setup IMO. It violates the principles of Swiss tournaments and pushes the code to the edge cases where there will be bugs.
A 20 person Swiss can be completed in 5-6 rounds with a clear winner declared. The ABSOLUTE maximum number of rounds in a 2 player Swiss tournament should be equal to half the number of players, 10 according BGA should actually require a Swiss tournament to have a minimum 2x players per match so minimum 40 players for 20 matches.
If everyone wants to play each other, just use the round robin format up to 15 players and schedule the games apart equal to the game duration so they get 1 game at a time. If you want more than 15 players and a high number of games, just use the Group Stage with round robin format, something like 2 groups of 10 and 5 from each group qualify for finals in a group of 10, that’s 18 matches. Don’t try to use Swiss outside its limits. Just my opinion, I’d prefer BGA devs to focus on improving tournament settings that apply to the existing tournament types for their intended purposes, not edge cases.
A 20 person Swiss can be completed in 5-6 rounds with a clear winner declared. The ABSOLUTE maximum number of rounds in a 2 player Swiss tournament should be equal to half the number of players, 10 according BGA should actually require a Swiss tournament to have a minimum 2x players per match so minimum 40 players for 20 matches.
If everyone wants to play each other, just use the round robin format up to 15 players and schedule the games apart equal to the game duration so they get 1 game at a time. If you want more than 15 players and a high number of games, just use the Group Stage with round robin format, something like 2 groups of 10 and 5 from each group qualify for finals in a group of 10, that’s 18 matches. Don’t try to use Swiss outside its limits. Just my opinion, I’d prefer BGA devs to focus on improving tournament settings that apply to the existing tournament types for their intended purposes, not edge cases.
Add something to this report
Please add here anything that seems relevant to reproduce this bug or understand your suggestion:
- Another table ID / move ID
- Did F5 solve the problem?
- Did the problem appears several time? Everytime? Randomly?
- If you have a screenshot of this bug (good practice), you can use Imgur.com to upload it and copy/paste the link here.
