Alliance selection determines which two teams pair up to compete together in the elimination matches at a VEX V5 or VEX AI Robotics Competition event, and sets the seeding for those matches. This article explains how qualification rankings are used, how the selection process runs, and what accepting or declining an invitation means for a team.
It is written for students, coaches, and organization administrators participating in VEX V5 and VEX AI Robotics Competition events.
Definitions of the terms used here are maintained in the central glossary.
Qualification Rankings
The results of qualification matches determine each team's ranking heading into alliance selection. Win points are earned by winning a match or by achieving the autonomous win point. Autonomous points are earned by winning the autonomous bonus at the start of a match. Strength of schedule points are the sum of the losing alliance's score in each qualification match a team has played.
Teams are ranked by average win points. If a tie remains, it is broken in the following order: average autonomous points, then average strength of schedule points, then the team's highest match score, then its second-highest match score, and finally a random electronic draw performed in the tournament manager (TM) software.
Alliance Selection
Immediately following the conclusion of qualification matches, each team sends one student representative to the playing field area for alliance selection. The first-ranked team serves as the alliance captain for the first seeded alliance and may invite any team at the event that has not already been selected to join an alliance.
Alliance selection moves quickly and happens without outside input, so teams are encouraged to watch other teams throughout the competition and discuss potential alliance partners as a team beforehand, arriving with their choices already decided. Because an invited team may decline, alliance captains should also have more than one potential partner in mind before making a selection.
After a Team Is Picked
After an alliance captain extends an invitation, the invited team's representative accepts or declines. If the invited team accepts, the alliance is complete and neither team remains available for further invitations.
If the invited team declines, it can no longer be selected by any other alliance captain for the remainder of alliance selection. The team may still form its own alliance if its ranking later allows it to become an alliance captain. A team that declines an invitation and never reaches an alliance captain position does not participate in the elimination round. Declining an invitation is a one-time decision, so a team should weigh it carefully before doing so.
Continuing the Process
After a team accepts an invitation, all teams ranked behind it move up one position. Alliance captains continue selecting partners in ranking order until every alliance is formed for the elimination matches.
This video walks through the full alliance selection process.
Number of Alliances
The number of alliances for a given event is determined by the number of teams at the event, as shown in the table below.
| Number of Teams | Number of Elimination Alliances |
| 32 or more | 16 |
| 24-31 | 12 |
| 16-23 | 8 |
| Fewer than 16 | Number of teams divided by 2, rounded down |
Elimination Bracket
Once alliance selection is concluded, the elimination bracket is finalized and the Round of 16 matchups are determined by the seed of each alliance.
16-Alliance Events
If the event is run with 16 alliances, the bracket and matchups are as shown below.
12-Alliance Events
If the event is run with 12 alliances, the bracket runs as shown below.
8-Alliance Events
If the event is run with 8 alliances, the bracket runs as shown below.