Rot-Jaune-Verde. Language and Favoritism: Evidence from Swiss Soccer

Switzerland is a multi-lingual developed country that provides an attractive stage to test ingroup favoritism that is driven by linguistic differences. To that end, we utilize data from soccer games in the top two Swiss divisions between the seasons 2005/06 and 2017/18. In these games, the referee was from the same linguistic area with one team, whereas the other team was from a different linguistic area. Using very rich data on teams’ and games’ characteristics, our causal forest-based estimator reveals that referees assign significantly more penalties in the form of yellow and red cards to teams from a different linguistic area. This form of ingroup favoritism is large enough so that it is likely to affect the outcome of the game. As evidence, we find that the difference in points in favor of the home team increases significantly when a referee is from the same linguistic area.