  Team composition is a central factor in determining the effectiveness of a
team. In this paper, we present a large-scale study on the effect of team
composition on multiple measures of team effectiveness. We use a dataset from
the largest multiplayer online battle arena (MOBA) game, Honor of Kings, with
96 million matches involving 100 million players. We measure team effectiveness
based on team performance (whether a team is going to win), team tenacity
(whether a team is going to surrender), and team rapport (whether a team uses
abusive language). Our results confirm the importance of team diversity and
show that diversity has varying effects on team effectiveness: although diverse
teams perform well and show tenacity in adversity, they are more likely to
abuse when losing than less diverse teams. Our study also contributes to the
situation vs. personality debate and show that abusive players tend to choose
the leading role and players do not become more abusive when taking such roles.
We further demonstrate the predictive power of features based on team
composition in prediction experiments.
