One of the most common tournament formats for regular season events is prelim groups followed by playoff groups. In some cases, it's most efficient to reset the standings at the mid-tournament rebracketing, but in other cases, it makes sense to carryover and crossover. That is, two (or more) teams are advancing to the same playoff bracket from the same prelim group. Rather than replay the game(s) between those teams in the afternoon, you carry over the result from the morning, and only play those games that are new. This post is meant to demonstrate some of the schedules which are possible, and how best to organize a crossover stage.
Terminology: Letters will indicate prelim groups, numbers will represent teams within those groups, in the order they finished the morning rounds. "Morning" indicates the preliminary stage, "Afternoon" the playoff stage, as in my region the split between the two stages is almost always lunchtime.
Example: Starting with 16 teams in 2 groups of 8, you might play a round-robin, and then split into top 4 and bottom 4 for crossover rounds. Then the teams in the top bracket are A1, A2, A3, A4; B1, B2, B3, B4. Each team enters the afternoon with 3 games already counting from the morning (note that A1 does not necessarily carry over 3 wins). Then a possible afternoon schedule is:
Code: Select all
Rd Rm #1 Rm #2 Rm #3 Rm #4
#1 A1-B4 A2-B3 A3-B2 A4-B1
#2 A4-B2 A3-B1 A2-B4 A1-B3
#3 A2-B1 A1-B2 A4-B3 A3-B4
#4 A3-B3 A4-B4 A1-B1 A2-B2
Where this gets difficult is when there are more than two prelim groups feeding into a crossover. I was inspired to create this thread while planning the format for ACF Nationals. Some potential formats involved a 15-team crossover, with 5 teams each coming from 3 groups. With each team having to play 10 games, can this be accomplished in 10 rounds? No, since with an odd number of teams, not everyone plays each round? Can it be done in 11? Yes. Is there an elegant way to create such a schedule? Maybe, but I brute forced it. It's the same kind of situation that occurred in the top tier of the 2013 NSC, where the top bracket had nine teams, the top three from each of three semifinal groups. Seven rounds, rather than six, were required because of the necessary byes. What about a case where the bottom bracket has three teams from group A, but two from groups B and C?
So the point of this thread, which I hope to build over the next week or two, is to compile crossover formats for differing numbers of teams, as a service to the QB community. If you have any feedback or schedules to contribute, feel free to chime in.