Difference between revisions of "Tournament structure"
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| − | '''Tournament | + | '''Tournament format''' refers to what matches are played at a tournament and how they relate to each other and to the tournament's standings. |
| − | == | + | ==Considerations== |
| − | + | When determining the tournament format, [[tournament directors]] must consider these factors and possibly others: | |
| + | * The need/desire to determine the winner, and preferably more places, as fairly as possible | ||
| + | * Teams' preferences | ||
| + | * The number of available question packets | ||
| + | * The number of available rooms | ||
| + | * The number of available staff members | ||
| + | * An appropriate amount of time for the tournament to last | ||
| + | * The desire to give teams as many games as is reasonably possible and appropriate in light of the entry fee they play (in the sense that giving teams one game before they go home is likely to be considered a ripoff) | ||
| + | There are, of course, tradeoffs among many of these factors. | ||
| − | == | + | Tournament directors often try to incorporate into their formats the principle that a single loss should never eliminate a team from championship contention. This is in large part because quizbowl is, by its nature, highly variable from packet to packet, and teams' skills can be sensitive to the luck inherent in what questions they happen to hear at particular times; the no-single-elimination principle therefore seeks to minimize the damage that one spot of bad luck can cause. (Here "no-single-elimination" does not only refer to avoiding single-elimination playoffs; other schemes, such as parallel playoff pools and power-matching, can amount to single-elimination in this sense.) |
| − | [[ | + | |
| − | + | ==Building blocks of formats== | |
| − | + | ===Round robin=== | |
| − | + | A '''round robin''' is a format in which every team plays every other team. A '''double round robin''' is a format in which every team plays every other team twice. '''Triple round robins''' and so forth mean what you think they should mean based on the previous sentence. | |
| − | [[ | + | |
| − | + | ===Pooled round robin=== | |
| − | This | + | A '''pooled round robin''' is a format in which the teams are divided into separate groups ("pools") and a round robin occurs within each group. For instance, a 24-team tournament might be split into four pools of six teams each. When this occurs, it is necessary to have some sort of [[playoff]] scheme to determine an overall winner. |
| − | + | ||
| − | This means that | + | When pools are used for preliminary rounds, it is considered a best practice to balance the overall strength of the pools as much as possible. This is done by seeding the teams (generally based on results from past tournaments and expected rosters for the current tournament) and then "snaking" the seeds into pools. For instance, in a 24-team tournament with four pools of six, one pool would contain the teams seeded 1, 8, 9, 16, 17, and 24; another pool would contain the teams seeded 2, 7, 10, 15, 18, and 23; another pool would contain the teams seeded 3, 6, 11, 14, 19, and 22; and the last pool would contain the remaining teams, viz., those seeded 4, 5, 12, 13, 20, and 21. If seeding is not possible due to a paucity of results, random draw is appropriate. Sometimes very small adjustments are made to keep apart teams from the same school or same area, or for other reasons. |
| + | |||
| + | When pools are used for playoff rounds, they are generally stratified. Our example tournament with 24 teams in four preliminary pools of six might be "rebracketed" for playoffs into three pools of eight. The top playoff pool ("championship pool") would contain the top two teams from each preliminary pool (based on record and, if necessary, [[tiebreaker games]] or [[points per tossup heard]]), the second playoff pool ("first consolation pool") would contain the middle two teams from each preliminary pool, and the third ("second consolation pool") would contain the bottom two teams from each preliminary pool. Each of these new pools would then play a round robin, though the games between teams who had been in the same preliminary pool would often not be replayed. | ||
| + | |||
| + | In some cases, '''parallel playoff pools''' are used. In our example with 24 teams in four preliminary pools of six, as an alternative to the previous scheme, there could be six playoff pools of four, where the top two pools each contain the first-place teams from two preliminary pools (by record and, if necessary, [[tiebreaker games]] or [[points per tossup heard]]) and the second-place teams from the other two), that is, there are two "parallel" championship pools. Each of these new pools would then play a round robin, and then the teams therein would be ranked (by record and, if necessary, tiebreaker games or points per tossup heard). The first-place teams in each parallel playoff pool would play each other in a final game for the overall tournament championship. Optionally, the second-place teams in each pool would play for overall third place, etc. Meanwhile, the 16 teams that did not make one of the two parallel playoff pools would be divided into consolation pools, possibly in parallel pairs or possibly not. | ||
| + | |||
| + | Pools are often referred to as "brackets" (hence the term "rebracket"), but that term can cause confusion with elimination brackets. ("Repooling" is pretty much unattested.) | ||
| + | |||
| + | ===Random pairings=== | ||
| + | Some tournaments have teams play games against essentially (or absolutely) random opponents, without any pooling scheme. | ||
| + | |||
| + | ===[[Power-matching]]=== | ||
| + | '''[[Power-matching]]''' is a scheme similar to [https://en.wikipedia.org/wiki/Swiss-system_tournament Swiss pairing], but without using results throughout the day to inform re-seeding. Typically, teams always face opponents who have the same record as them, or as similar a record is possible. Power-matching is often implemented by means of a [[card system]], though there are other ways. Power-matching on its own is logically equivalent to an elimination tournament with built-in consolation games. | ||
| + | |||
| + | ===Elimination tournaments=== | ||
| + | '''Single-elimination''' is a system in which a team is eliminated from contention as soon as it loses a match. Meanwhile, winners go on and face other winners. This format is moderately popular for playoffs (generally after preliminary games, often by means of pools) and very popular for [[television tournaments]]. It is often criticized for giving teams relatively few games (which can be considered a waste of money, lead B teams to have nothing to do but wait while the A team is still competing, etc.), but it is very efficient in terms of getting to a winner in a minimum number of games and rounds. | ||
| + | |||
| + | '''Double-elimination''' is a system in which a team is eliminated from contention as soon as it has lost ''two'' matches. After each round, winners face winners in the next round in a "winner's bracket", while losers drop down into a "loser's bracket". Play proceeds until either one team is left in the winner's bracket and one is left in the loser's bracket, in which case they play an advantaged final (the winner's bracket team can win the championship by winning one game; the loser's bracket team would have to win twice consecutively to claim the championship), or there are two remaining teams both in the loser's bracket, in which case they play a single championship match. Double-elimination is rare in quizbowl because unless there are very many teams, it takes more rounds than round robin-based playoffs, but it is used at several [[NAQT]] national championships. | ||
| + | |||
| + | (Triple-elimination and higher-order elimination formats are theoretically possible, but unheard of in quizbowl.) | ||
| + | |||
| + | The [[HSNCT]] uses a hybrid single/double-elimination playoff format: after each team plays 10 preliminary games, there is a double-elimination tournament but teams who went 6-4 in the preliminary rounds start in the loser's bracket. That is, teams who went 6-4 will be eliminated on their first loss, while teams who went 7-3 or better will be eliminated on their second loss. (Teams who went 5-5 or worse are not in the playoffs.) | ||
| + | |||
| + | ===Advantaged final=== | ||
| + | In many tournaments, when one team is exactly one game ahead of a second-place team, an '''advantaged final''' occurs. This means that up to two matches will be played. If the team that started ahead wins the first game, it is the champion. If the team that started behind wins the first game, the second game is "winner-take-all". This is equivalent to a best-of-three series in which the initially-leading team is considered to have already won the first game, and is therefore said to be "advantaged" (and the initially-trailing team is said to be "disadvantaged"). | ||
| + | |||
| + | When there are multiple second-place teams one game behind the leader, typically [[tiebreaker matches]] occur to determine which of them will face the leader in an advantaged final. | ||
| + | |||
| + | The term "advantaged final" was coined by [[Robert Hentzel]]. | ||
==External Links== | ==External Links== | ||
Revision as of 21:08, 21 November 2017
Tournament format refers to what matches are played at a tournament and how they relate to each other and to the tournament's standings.
Considerations
When determining the tournament format, tournament directors must consider these factors and possibly others:
- The need/desire to determine the winner, and preferably more places, as fairly as possible
- Teams' preferences
- The number of available question packets
- The number of available rooms
- The number of available staff members
- An appropriate amount of time for the tournament to last
- The desire to give teams as many games as is reasonably possible and appropriate in light of the entry fee they play (in the sense that giving teams one game before they go home is likely to be considered a ripoff)
There are, of course, tradeoffs among many of these factors.
Tournament directors often try to incorporate into their formats the principle that a single loss should never eliminate a team from championship contention. This is in large part because quizbowl is, by its nature, highly variable from packet to packet, and teams' skills can be sensitive to the luck inherent in what questions they happen to hear at particular times; the no-single-elimination principle therefore seeks to minimize the damage that one spot of bad luck can cause. (Here "no-single-elimination" does not only refer to avoiding single-elimination playoffs; other schemes, such as parallel playoff pools and power-matching, can amount to single-elimination in this sense.)
Building blocks of formats
Round robin
A round robin is a format in which every team plays every other team. A double round robin is a format in which every team plays every other team twice. Triple round robins and so forth mean what you think they should mean based on the previous sentence.
Pooled round robin
A pooled round robin is a format in which the teams are divided into separate groups ("pools") and a round robin occurs within each group. For instance, a 24-team tournament might be split into four pools of six teams each. When this occurs, it is necessary to have some sort of playoff scheme to determine an overall winner.
When pools are used for preliminary rounds, it is considered a best practice to balance the overall strength of the pools as much as possible. This is done by seeding the teams (generally based on results from past tournaments and expected rosters for the current tournament) and then "snaking" the seeds into pools. For instance, in a 24-team tournament with four pools of six, one pool would contain the teams seeded 1, 8, 9, 16, 17, and 24; another pool would contain the teams seeded 2, 7, 10, 15, 18, and 23; another pool would contain the teams seeded 3, 6, 11, 14, 19, and 22; and the last pool would contain the remaining teams, viz., those seeded 4, 5, 12, 13, 20, and 21. If seeding is not possible due to a paucity of results, random draw is appropriate. Sometimes very small adjustments are made to keep apart teams from the same school or same area, or for other reasons.
When pools are used for playoff rounds, they are generally stratified. Our example tournament with 24 teams in four preliminary pools of six might be "rebracketed" for playoffs into three pools of eight. The top playoff pool ("championship pool") would contain the top two teams from each preliminary pool (based on record and, if necessary, tiebreaker games or points per tossup heard), the second playoff pool ("first consolation pool") would contain the middle two teams from each preliminary pool, and the third ("second consolation pool") would contain the bottom two teams from each preliminary pool. Each of these new pools would then play a round robin, though the games between teams who had been in the same preliminary pool would often not be replayed.
In some cases, parallel playoff pools are used. In our example with 24 teams in four preliminary pools of six, as an alternative to the previous scheme, there could be six playoff pools of four, where the top two pools each contain the first-place teams from two preliminary pools (by record and, if necessary, tiebreaker games or points per tossup heard) and the second-place teams from the other two), that is, there are two "parallel" championship pools. Each of these new pools would then play a round robin, and then the teams therein would be ranked (by record and, if necessary, tiebreaker games or points per tossup heard). The first-place teams in each parallel playoff pool would play each other in a final game for the overall tournament championship. Optionally, the second-place teams in each pool would play for overall third place, etc. Meanwhile, the 16 teams that did not make one of the two parallel playoff pools would be divided into consolation pools, possibly in parallel pairs or possibly not.
Pools are often referred to as "brackets" (hence the term "rebracket"), but that term can cause confusion with elimination brackets. ("Repooling" is pretty much unattested.)
Random pairings
Some tournaments have teams play games against essentially (or absolutely) random opponents, without any pooling scheme.
Power-matching
Power-matching is a scheme similar to Swiss pairing, but without using results throughout the day to inform re-seeding. Typically, teams always face opponents who have the same record as them, or as similar a record is possible. Power-matching is often implemented by means of a card system, though there are other ways. Power-matching on its own is logically equivalent to an elimination tournament with built-in consolation games.
Elimination tournaments
Single-elimination is a system in which a team is eliminated from contention as soon as it loses a match. Meanwhile, winners go on and face other winners. This format is moderately popular for playoffs (generally after preliminary games, often by means of pools) and very popular for television tournaments. It is often criticized for giving teams relatively few games (which can be considered a waste of money, lead B teams to have nothing to do but wait while the A team is still competing, etc.), but it is very efficient in terms of getting to a winner in a minimum number of games and rounds.
Double-elimination is a system in which a team is eliminated from contention as soon as it has lost two matches. After each round, winners face winners in the next round in a "winner's bracket", while losers drop down into a "loser's bracket". Play proceeds until either one team is left in the winner's bracket and one is left in the loser's bracket, in which case they play an advantaged final (the winner's bracket team can win the championship by winning one game; the loser's bracket team would have to win twice consecutively to claim the championship), or there are two remaining teams both in the loser's bracket, in which case they play a single championship match. Double-elimination is rare in quizbowl because unless there are very many teams, it takes more rounds than round robin-based playoffs, but it is used at several NAQT national championships.
(Triple-elimination and higher-order elimination formats are theoretically possible, but unheard of in quizbowl.)
The HSNCT uses a hybrid single/double-elimination playoff format: after each team plays 10 preliminary games, there is a double-elimination tournament but teams who went 6-4 in the preliminary rounds start in the loser's bracket. That is, teams who went 6-4 will be eliminated on their first loss, while teams who went 7-3 or better will be eliminated on their second loss. (Teams who went 5-5 or worse are not in the playoffs.)
Advantaged final
In many tournaments, when one team is exactly one game ahead of a second-place team, an advantaged final occurs. This means that up to two matches will be played. If the team that started ahead wins the first game, it is the champion. If the team that started behind wins the first game, the second game is "winner-take-all". This is equivalent to a best-of-three series in which the initially-leading team is considered to have already won the first game, and is therefore said to be "advantaged" (and the initially-trailing team is said to be "disadvantaged").
When there are multiple second-place teams one game behind the leader, typically tiebreaker matches occur to determine which of them will face the leader in an advantaged final.
The term "advantaged final" was coined by Robert Hentzel.