School ties and evaluation outcomes: Evidence from the Korean Basketball League

This paper investigates whether evaluation outcomes are influenced by private information and subjective biases when appraisers and appraisees are socially connected. In the Korean Basketball League, school ties between referees and players are commonplace because a large proportion of referees were previously basketball players. Using data from six basketball seasons, we analyze the degree to which referees' decisions are affected when players and referees attended the same school. Our results suggest that players who play under referees with school ties are called for fewer fouls. We also find that the results are driven mainly by high school ties.