Double Knockout Tournament Format
Double Knockout Tournament Format, also known as Double Elimination, is a format for pairing players to play games in tournaments.
In the first round, players are paired to play. Those players that lose are moved to the losers bracket. Those players that win, are promoted to the second round. This second round and all its subsequent rounds are known as the winners bracket. This procedure is repeated till only a single player remains. This player is the winner of the winners bracket.
The losers bracket players play single knockout tournament. The winner of that tournament is winner of the losers bracket.
The winner of the winners bracket plays the winner of the losers bracket to determine the winner of the double knockout tournament.
Double knockout tournaments take a few more rounds than single knockout tournaments. This is because the size of the losers bracket does not quite divide by two each round. Half the members of the losers bracket are eliminated, but half the members of the winners bracket get moved to the losers bracket. This requires a few extra rounds to complete the losers bracket.
As a rule of thumb,
For tournaments of size 8 - 40, the number or rounds is roughly 3 more than log base 2 of tournament size.
For tournaments of size 41 - 800, the number or rounds is roughly 4 more than log base 2 of tournament size.
For larger tournaments, the number or rounds is roughly 5 more than log base 2 of tournament size. (This trend continues at least through size 30 000.
See also:
- Jeff Sonas? on various
formats for running a double elimination tournament.
-
Double-Elimination Tournaments: Counting and Calculating by Christopher T. Edwards published in The American Statistician February 1996
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http://en.wikipedia.org/wiki/Double-elimination_tournament