A knockout tournament or elimination tournament is divided into successive rounds; each competitor plays in at least one fixture per round. The top-ranked competitors in each fixture progress to the next round. As rounds progress, the number of competitors and fixtures decreases. The final round, usually known as the final or cup final, consists of just one fixture; the winner of which is the overall champion.
In a single-elimination tournament, only the top-ranked competitors in a fixture progress; in 2-competitor games, only the winner progresses. All other competitors are eliminated. This ensures a winner is decided with the minimum number of fixtures. However, most competitors will be eliminated after relatively few matches; a single bad or unlucky performance can nullify many preceding excellent ones.
A double-elimination tournament may be used in 2-competitor games to allow each competitor a single loss without being eliminated from the tournament. All losers from the main bracket enter a losers' bracket, the winner of which plays off against the main bracket's winner.
A triple-elimination tournament allows a competitor to lose two games and creates a third bracket or fourth bracket which are usually followed by a playoff. It is commonly used in curling tournaments.
Some elimination tournaments are in a best-of-n series, requiring a competitor to lose a majority of n games (in a series against the same opponent) before being eliminated (e.g. in a best-of-7 games series, the winner must win 4 games).
An extreme form of the knockout tournament is the stepladder format where the strongest team (or individual, depending on the sport) is assured of a berth at the final round while the next strongest teams are given byes according to their strength/seeds; for example, in a four team tournament, the fourth and third seed figure in the first round, then the winner goes to the semifinals against the second seed, while the survivor faces the first seed at the final. Four American sports organizations either currently use this format, or have in the past:
A group tournament, league, division or conference involves all competitors playing a number of fixtures (again, a fixture is one name for a tournament-match that determines who, out of two or three or more, will advance; a fixture may consist of one or more game-matches between competitors). Points are awarded for each fixture, with competitors ranked based either on total number of points or average points per fixture. Usually each competitor plays an equal number of fixtures, in which case rankings by total points and by average points are equivalent. The English County Championship in cricket did not require an equal number of matches prior to 1963.[2]
In a round-robin tournament, each competitor plays all the others an equal number of times, once in a single round-robin tournament and twice in a double round-robin tournament. This is often seen as producing the most reliable rankings. However, for large numbers of competitors it may require an unfeasibly large number of rounds. A Swiss system tournament attempts to determine a winner reliably, based on a smaller number of fixtures. Unlike regular Groups format, fixtures are scheduled one round at a time and depending on the results of the previous one; a competitor will play another who has a similar record in previous rounds of the tournament. This allows the top (and bottom) competitors to be determined with fewer rounds than a round-robin, though the middle rankings are unreliable.
Another tournament system that attempts to reduce the number of fixtures per competitor is the Pot System. Under that system, competitors are divided to different "pots" based on predetermined ranking and are drawn to play one rival from each pot, including their own pot. For example, in a 36-team World Cup, teams would be divided into 3 pots, with each team playing 3 matches - one against a Pot A team, one against Pot B team, and one against a team from Pot C. All teams are then placed in one general standing the defines qualification to the following stage.[4]
The primary objective of a tournament is to determine the winner of a competition. Ideally, the tournament should be designed in such a way that all participants have an equal chance to compete and progress, regardless of factors like seeding or scheduling. The influence of luck or chance on the results should be minimised. The tournament should also be an exciting and engaging event for participants and spectators. Hence the following requirements for an ideal tournament:
A multi-stage pool system was implemented by Curling Canada for the Canadian championship curling tournaments (the Scotties Tournament of Hearts for women and the Montana's Brier for men) starting in 2018. The change was intended to allow the expansion of the main stage of the tournament from twelve to sixteen teams while keeping the round robin at eleven games. The teams are seeded using a ranking system in which points are calculated based on the teams' results in all competitive bonspiels using a complicated formula. Seeds 1, 4, 5, 8, 9, 12, 13 and 16 and placed in Pool A while seeds 2, 3, 6, 7, 10, 11, 14 and 15 are placed in Pool B. After each team has played seven games, the top four teams from each pool advance to the "Championship Pool." Carrying over their entire round robin records with them, Championship Pool teams play one game against each of the four teams in the opposite pool, with the top four teams qualifying for the page playoffs. In contrast, teams that fail to qualify for the Championship Pool play only one additional "Placement Round" game against the team that finished in the same position in the opposite pool for the purposes of determining final tournament ranking. For these teams, there is little else to play for since there is no form of relegation (and, with the expansion of the field to sixteen teams, no "pre-qualifying tournament") and seeding is based solely on the performances of the participating teams and not the past results of the provinces and territories they represent.
In many international team events, such as World Cups or Olympic tournaments, different variants of the combination of the group stage (round-robin tournament) and the knockout stage (single-elimination tournament) are used. Such tournaments have significant structural problems that lead, among other things, to the violation of fair play. The following classification of these problems, with examples from football championships, applies in principle to tournaments in all other sports.
If two such teams meet in the last group match, then it will not have a major tournament impact. It is just a training match with no relevance to the championship. However, such meaningless matches are not always advantageous for the already qualified teams. The game rhythm is lost and the team may have difficulties finding it in the next game.
In such "fair play potentially problematic" constellations, the violation of fair play in one way or another is possible and not excluded by the rules of the tournament format. In most cases, even in these constellations, the matches are played according to fair play and there are no repercussions for the other teams in the group. Nevertheless, this possibility exists, which can lead to irritations around the matches. Sometimes, in these cases, the teams concerned even feel compelled to assure that no arrangements are made, as was the case at the 2014 World Cup before the final group match between Germany and the USA.
In some cases, however, there might be a motivation for teams to finish first in their group, especially if a top favorite is waiting for the group runner-up. If, however, the top favorite surprisingly finished second in its group and now faces the group winner, then it will be an advantage to finish second. According to the tournament format, winning in this case paradoxically reduces the chances of advancing. This was particularly illustrated in the scandal at the 2012 Olympic badminton tournament.[11] Several participants in the badminton tournament were disqualified because they had tried to get easier competitors or a better starting position for the final stage by losing. Sometimes neither of the participants was really willing to leave the field as the winner. The championships of all sports are not immune to such constellations.
In the knockout stage, the format single-elimination tournament is used. This format is most efficient to determine the winner quickly with the smallest possible number of matches. And it is the most ineffective to determine the actual best team as the winner with the highest possible probability. The poor performance of the single-elimination tournament can be explained by the fact that a team is eliminated from the tournament after a single defeat. Even the best team can occasionally lose, for example in a penalty shoot-out. In addition, the stronger teams can meet in the earlier rounds and eliminate each other from the tournament. Thus, the number of "better" teams is reduced and "weaker" teams get more chances to become tournament winner.
 983975eaba