Difference between revisions of "Tournament structure"
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| − | '''Tournament format''' refers to what matches are played at a tournament and how they relate to each other and to the tournament's standings. | + | '''Tournament format''' refers to what matches are played at a tournament and how they relate to each other and to the tournament's standings. (The same phrase is also sometimes used to refer the set of [[rules]] used at a tournament.) |
==Considerations== | ==Considerations== | ||
| Line 19: | Line 19: | ||
* Varsity and Frosh-Soph (high school tournaments) | * Varsity and Frosh-Soph (high school tournaments) | ||
* Competitive and Less Competitive (middle and high school tournaments; known by a variety of names) | * Competitive and Less Competitive (middle and high school tournaments; known by a variety of names) | ||
| − | * [[Division I | + | * [[Division I and Division II]] (college tournaments) |
* [[Open]] and [[Undergraduate]] (college tournaments) | * [[Open]] and [[Undergraduate]] (college tournaments) | ||
* Public Schools and Private Schools (middle and high school tournaments) | * Public Schools and Private Schools (middle and high school tournaments) | ||
| Line 37: | Line 37: | ||
==Building blocks of formats== | ==Building blocks of formats== | ||
| + | The following setups are called "building blocks" because they can be combined to form tournaments. For instance, it's common to have pooled round robin preliminary rounds followed by single-elimination playoffs. The "building blocks" can generally also be used on their own, and not all combinations make sense. | ||
| + | |||
===Round robin=== | ===Round robin=== | ||
| + | :''See also: [[round robin]]'' | ||
A '''round robin''' is a format in which every team plays every other team. This extends to formats where each team plays every other team the same number of times: '''double round robin''', '''triple round robin''', etc. | A '''round robin''' is a format in which every team plays every other team. This extends to formats where each team plays every other team the same number of times: '''double round robin''', '''triple round robin''', etc. | ||
| − | |||
| − | |||
| − | |||
===Pooled round robin=== | ===Pooled round robin=== | ||
| Line 67: | Line 67: | ||
If there are not enough available results to seed the teams, 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. | If there are not enough available results to seed the teams, 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 (the preliminary game is said to '''carry over'''). | + | 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 (the preliminary game is said to '''carry over'''). Opinions differ as whether the teams should be ranked by pool followed by overall record (including both preliminary and playoff games) or pool followed by playoff record only. (In either case, ties could be left as ties, broken by [[tiebreaker games]], or broken by another [[statistics|statistical measure]] such as [[points per tossup heard]]. Ties for first place are essentially always broken by a tiebreaker game.) |
Sometimes, '''wild cards''' are used to fill out the playoff pools when the playoff pool size is not evenly divisible by the number of preliminary pools. In our example tournament, an alternative format would be to rebracket into four pools of six for the playoffs. The pools would be determined as follows: | Sometimes, '''wild cards''' are used to fill out the playoff pools when the playoff pool size is not evenly divisible by the number of preliminary pools. In our example tournament, an alternative format would be to rebracket into four pools of six for the playoffs. The pools would be determined as follows: | ||
| Line 78: | Line 78: | ||
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.) | 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.) | ||
| + | |||
| + | ===Fractional round robin=== | ||
| + | For some field sizes, a single round robin would be considered too few rounds but a double round robin would be too many rounds. In this case, a single round robin may occur followed by breaking into tiered playoff pools. For instance, an eight-team tournament might play a round robin (rounds 1–7), then place the top four teams (by record, and if necessary [[tiebreaker games]] or [[statistical tiebreakers]]) in a top playoff pool and the bottom four teams in a bottom playoff pool; each playoff pool would then play a (pooled) round robin (rounds 8–10). | ||
===Random pairings=== | ===Random pairings=== | ||
Some tournaments have teams play games against essentially (or absolutely) random opponents, without any pooling scheme. | Some tournaments have teams play games against essentially (or absolutely) random opponents, without any pooling scheme. | ||
| − | === | + | ===Power-matching=== |
| − | '' | + | :''See also: [[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 similar to an elimination tournament with built-in consolation games (though there are differences in some of the specific pairings). | ||
===Elimination tournaments=== | ===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. | + | '''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]] (because it guarantees a specific number of games and allows as many teams to participate as possible given that the games are not played concurrently). 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 "winners' bracket", while losers drop down into a "losers' bracket". Play proceeds until either one team is left in the winners' bracket and one is left in the losers' bracket, in which case they play an advantaged final (the winners' bracket team can win the championship by winning one game; the losers' bracket team would have to win twice consecutively to claim the championship), or there are two remaining teams both in the losers' 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. | '''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 "winners' bracket", while losers drop down into a "losers' bracket". Play proceeds until either one team is left in the winners' bracket and one is left in the losers' bracket, in which case they play an advantaged final (the winners' bracket team can win the championship by winning one game; the losers' bracket team would have to win twice consecutively to claim the championship), or there are two remaining teams both in the losers' 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 almost unheard of in quizbowl - as a true "playoff phase" of a tournament it takes so many rounds for any field size that you could just do pooled playoffs instead, and there is no realistic scenario where it is a practical solution. The only near-exception was the format used at [[ASCN TOC]], in which teams played randomly drawn prelim games until all but a neat number (e.g. 16 or 24) had 3 losses, at which point all teams with fewer than 3 losses were seeded into a single-elimination playoff bracket. Thus, the tournament was "triple elimination" for the cut from prelims to playoffs only. | |
The [[HSNCT]] uses a hybrid single/double-elimination playoff format: after each team plays 10 preliminary games, all teams that went 6-4 or better in the preliminary rounds participate in a double-elimination tournament. However, teams who went 6-4 in the preliminary rounds start in the losers' 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. | The [[HSNCT]] uses a hybrid single/double-elimination playoff format: after each team plays 10 preliminary games, all teams that went 6-4 or better in the preliminary rounds participate in a double-elimination tournament. However, teams who went 6-4 in the preliminary rounds start in the losers' 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. | ||
| − | === | + | ===Final=== |
| − | + | Tournaments generally need some sort of finals format. | |
| + | |||
| + | Elimination playoffs have the final built in. | ||
| + | |||
| + | One can simply declare that the top team after playoffs is the winner of the tournament, but that entails defining "top team", including defining a scheme for breaking ties. | ||
| − | + | Sometimes finals procedures are applied recursively to identify lower-down places, e.g. for awarding trophies. | |
| − | The term "advantaged final" was coined by [[Robert Hentzel]]. | + | ===ACF-style final and advantaged finals=== |
| + | :''"Two-game final" and "advantaged final" redirect here.'' | ||
| + | Many tournaments typically use the following scheme for finals: | ||
| + | * If the top team by record (in the singular top pool) is at least two games ahead of the second-place team(s) (in the same pool), the top team is the winner of the tournament; they are said to have '''cleared the field''' by obviating the need for a final | ||
| + | * If there is an exact tie in record for first place, a single-game final occurs (the winner of which is the winner of the tournament) | ||
| + | * If the top team by record is exactly one game ahead of the second-place team(s), an '''advantaged final''' occurs: Up to two matches will be played; if the team that was originally in first place wins the first, it wins the tournament, while if the team that was originally in second place wins the first game, a second game is played and the winner is the winner of the tournament. This is equivalent to a best-of-three series in which the initially-first-place team is considered to have already won the first game, and is therefore said to be "advantaged" (and the initially-second-place team is said to be "disadvantaged). | ||
| + | ** If there is a tie for second place, one game behind first place, [[tiebreaker|tiebreaking procedures]] will be necessary to determine which of the second-place teams faces the first-place team; this requires additional rounds and questions. If time is short and/or questions are not available, the top team may be declared the winner because there is no fair way to determine which second-place team should have the opportunity to play for first, or [[statistical tiebreakers]] may be used to determine which second-place team has that opportunity, though the latter is not a best practice. | ||
| + | ** The term "advantaged final" was coined by [[Robert Hentzel]]. | ||
| + | This scheme is sometimes called an '''ACF final''' or '''ACF-style final''', even though it is used by many non-ACF tournaments (including, more or less, the [[ICT]]). Sometimes the term '''advantaged final''' is incorrectly used for the entire scheme. | ||
==External Links== | ==External Links== | ||
Latest revision as of 20:04, 10 August 2023
Tournament format refers to what matches are played at a tournament and how they relate to each other and to the tournament's standings. (The same phrase is also sometimes used to refer the set of rules used at a tournament.)
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.)
Divisions
Tournaments are sometimes split into divisions, each of which is essentially a separate tournament; teams only play against teams in the same division. Divisions can be set up to offer teams or tournament directors choice in which teams are in which division, or so that there is no choice. Popular combinations of divisions include the following:
- Varsity and Junior Varsity/Novice (middle and high school tournaments)
- Varsity and Frosh-Soph (high school tournaments)
- Competitive and Less Competitive (middle and high school tournaments; known by a variety of names)
- Division I and Division II (college tournaments)
- Open and Undergraduate (college tournaments)
- Public Schools and Private Schools (middle and high school tournaments)
- High School and Middle School (for most purposes, two separate tournaments that happen to be at the same site on the same day)
- Groupings according to school size (middle and high school tournaments)
- A Teams and B(/subsequent) Teams
These can be combined (e.g. a tournament might have a High School Varsity division, a High School Junior Varsity division, and a Middle School division).
Sometimes divisions of the same tournament use the same packet set and sometimes they don't.
Reasons for creating divisions include the following:
- Allowing more teams to play but keeping each group smaller to make it easier to have a fair tournament format
- Giving weak or new teams and/or players an opportunity to "get their feet wet" without facing many very experienced teams
- Allowing separate question sets to be used in each division (a competitive team might use a harder set than the standard division at the same tournament).
Since divisions run more or less independently, the rest of this article could really be considered to be about the format for each division of a tournament, but the term "tournament" will be used anyway. There are still some cross-division considerations when planning a multi-division tournament; for instance, the divisions should be expected to end at similar times, especially if schools have teams in multiple divisions.
Building blocks of formats
The following setups are called "building blocks" because they can be combined to form tournaments. For instance, it's common to have pooled round robin preliminary rounds followed by single-elimination playoffs. The "building blocks" can generally also be used on their own, and not all combinations make sense.
Round robin
- See also: round robin
A round robin is a format in which every team plays every other team. This extends to formats where each team plays every other team the same number of times: double round robin, triple round robin, etc.
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. Here's an example for a 24-team tournament (four pools of 6):
| Pool A | Pool B | Pool C | Pool D |
|---|---|---|---|
| 1 | 2 | 3 | 4 |
| 8 | 7 | 6 | 5 |
| 9 | 10 | 11 | 12 |
| 16 | 15 | 14 | 13 |
| 17 | 18 | 19 | 20 |
| 24 | 23 | 22 | 21 |
If there are not enough available results to seed the teams, 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 (the preliminary game is said to carry over). Opinions differ as whether the teams should be ranked by pool followed by overall record (including both preliminary and playoff games) or pool followed by playoff record only. (In either case, ties could be left as ties, broken by tiebreaker games, or broken by another statistical measure such as points per tossup heard. Ties for first place are essentially always broken by a tiebreaker game.)
Sometimes, wild cards are used to fill out the playoff pools when the playoff pool size is not evenly divisible by the number of preliminary pools. In our example tournament, an alternative format would be to rebracket into four pools of six for the playoffs. The pools would be determined as follows:
- Championship: the four 1st-place teams, plus the two 2nd-place teams with the highest values of some (pre-announced) statistic.
- Consolation 1: the two remaining 2nd-place teams, plus the four 3rd-place teams.
- Consolation 2: the four 4th-place teams, plus the two 5th-place teams with the highest values of some statistic.
- Consolation 3: the two remaining 5th-place teams, plus the four 6th-place teams.
Sometimes, parallel playoff pools are used. In our example with 24 teams in four preliminary pools of six, as an alternative to the previous schemes, 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. In another variant, the top two teams from each championship pool play in semifinals (each first place team against the second place team from the other pool), with the winners proceeding to a one-game final.
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.)
Fractional round robin
For some field sizes, a single round robin would be considered too few rounds but a double round robin would be too many rounds. In this case, a single round robin may occur followed by breaking into tiered playoff pools. For instance, an eight-team tournament might play a round robin (rounds 1–7), then place the top four teams (by record, and if necessary tiebreaker games or statistical tiebreakers) in a top playoff pool and the bottom four teams in a bottom playoff pool; each playoff pool would then play a (pooled) round robin (rounds 8–10).
Random pairings
Some tournaments have teams play games against essentially (or absolutely) random opponents, without any pooling scheme.
Power-matching
- See also: 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 similar to an elimination tournament with built-in consolation games (though there are differences in some of the specific pairings).
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 (because it guarantees a specific number of games and allows as many teams to participate as possible given that the games are not played concurrently). 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 "winners' bracket", while losers drop down into a "losers' bracket". Play proceeds until either one team is left in the winners' bracket and one is left in the losers' bracket, in which case they play an advantaged final (the winners' bracket team can win the championship by winning one game; the losers' bracket team would have to win twice consecutively to claim the championship), or there are two remaining teams both in the losers' 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 almost unheard of in quizbowl - as a true "playoff phase" of a tournament it takes so many rounds for any field size that you could just do pooled playoffs instead, and there is no realistic scenario where it is a practical solution. The only near-exception was the format used at ASCN TOC, in which teams played randomly drawn prelim games until all but a neat number (e.g. 16 or 24) had 3 losses, at which point all teams with fewer than 3 losses were seeded into a single-elimination playoff bracket. Thus, the tournament was "triple elimination" for the cut from prelims to playoffs only.
The HSNCT uses a hybrid single/double-elimination playoff format: after each team plays 10 preliminary games, all teams that went 6-4 or better in the preliminary rounds participate in a double-elimination tournament. However, teams who went 6-4 in the preliminary rounds start in the losers' 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.
Final
Tournaments generally need some sort of finals format.
Elimination playoffs have the final built in.
One can simply declare that the top team after playoffs is the winner of the tournament, but that entails defining "top team", including defining a scheme for breaking ties.
Sometimes finals procedures are applied recursively to identify lower-down places, e.g. for awarding trophies.
ACF-style final and advantaged finals
- "Two-game final" and "advantaged final" redirect here.
Many tournaments typically use the following scheme for finals:
- If the top team by record (in the singular top pool) is at least two games ahead of the second-place team(s) (in the same pool), the top team is the winner of the tournament; they are said to have cleared the field by obviating the need for a final
- If there is an exact tie in record for first place, a single-game final occurs (the winner of which is the winner of the tournament)
- If the top team by record is exactly one game ahead of the second-place team(s), an advantaged final occurs: Up to two matches will be played; if the team that was originally in first place wins the first, it wins the tournament, while if the team that was originally in second place wins the first game, a second game is played and the winner is the winner of the tournament. This is equivalent to a best-of-three series in which the initially-first-place team is considered to have already won the first game, and is therefore said to be "advantaged" (and the initially-second-place team is said to be "disadvantaged).
- If there is a tie for second place, one game behind first place, tiebreaking procedures will be necessary to determine which of the second-place teams faces the first-place team; this requires additional rounds and questions. If time is short and/or questions are not available, the top team may be declared the winner because there is no fair way to determine which second-place team should have the opportunity to play for first, or statistical tiebreakers may be used to determine which second-place team has that opportunity, though the latter is not a best practice.
- The term "advantaged final" was coined by Robert Hentzel.
This scheme is sometimes called an ACF final or ACF-style final, even though it is used by many non-ACF tournaments (including, more or less, the ICT). Sometimes the term advantaged final is incorrectly used for the entire scheme.