Surrender at 20? Matchmaking in league of legends

Online games rely upon matchmaking systems to group players into teams and to match teams against other teams for balanced, fun gameplay. Despite the importance of matchmaking, little has been published about the effectiveness of current matchmaking systems. This paper presents the results from a detailed user study analyzing the matchmaking system for League of Legends (LoL), a popular online game. Analysis of objective and subjective data from over 50 games shows LoL games are balanced based on player ranks, but are unbalanced based on player opinions. Despite this, unbalanced games are often the most fun for players, as long as they are on the winning team. This last result suggests new considerations for matchmaking system algorithms.