TrueSkill
TrueSkill is a Bayesian rating system designed for multiplayer video games, developed by Microsoft Research and deployed on Xbox Live to rank players and support matchmaking. It generalizes the Elo rating approach to handle multiple players and varying team sizes, updating skill estimates as players compete and their performance becomes known.
In TrueSkill, each player's true skill s_i is modeled as a Gaussian distribution with mean mu_i and
The system supports teams of any size, treating each team’s performance as a sum of individual performances
Compared with Elo, TrueSkill explicitly accounts for uncertainty, supports variable team composition and multi-player games, and