Experience point
From Halopedia, the Halo wiki
EXP (Experience Points) are awarded to players based on their performance in a Halo 3 multiplayer match. Along with skill, EXP determines a player's rank. Points are awarded thusly[1]:
- Win: 1 EXP
- Lose: 0 EXP
- Quit: -1 EXP
In a free-for-all match, a player is considered to have won 1 EXP if he finishes in the top half, or in a team match, a player wins if his team wins.