Singles
A singles tournament is one in which players play as individuals rather than on teams. Most singles tournaments are tossup-only. At the high-school level, there are two national championship singles tournaments: NAQT's IPNCT (Individual Player National Championship Tournament), which features a mix of group and head-to-head matches, and NHBB's National History Bee, which is in a bee format. Besides those two, most singles tournaments are side events or online packet readings rather than main events, and do not use head-to-head or bee formats.
When a singles tournament's field is small, it is often run as a shootout, in which all players compete in a single room. The winner is usually decided by total points scored.
Larger singles tournaments are usually structured as a ladder, in which there are multiple rooms, ordered by skill. After each round, a certain number of players are shifted from one room to another. For example, a typical 24-player ladder format consists of three rooms of 8 players each. After each round, the bottom 2 players of the top room move down to the middle room, the top 2 and bottom 2 players of the middle room move up and down respectively, and the top 2 players in the bottom room move up.
Most ladder formats decide a winner using one of the following two systems: (1) cumulative score in the top room; (2) saving the last packet or two of the tournament as finals, which is effectively a shootout among whichever players end up in the top room after the conclusion of the pre-finals packets. A less common alternative (devised by John Lawrence) is a variable-scoring ladder, in which questions in each room are worth at least thrice the value of those in the next room down. (For example, gets and negs might be worth 10 and -5 in the bottom room, 30 and -15 in the middle room, etc.) The winner is determined by total cumulative score. The supposed advantage of this is that every tossup counts in every room and every player is ranked, even if they never reach the top room.