Abstract des Autors

There is evidence to suggest that referees in association football (soccer) show bias towards the home team when making decisions, and that this is at least partly due to home crowd influence. Match data from the Union of European Football Associations (UEFA) Europa League were used to investigate the association between referee expertise and the number of disciplinary sanctions issued to home and away teams. Poisson regression was used to estimate the mean number of yellow cards (cautions) received by home and away teams. Referee expertise was based on ranking categories used by UEFA. After controlling for potential confounders such as crowd density and stage of competition, the tendency for referees to issue more yellow cards to away teams than to home teams decreased with increasing expertise (p<0.05), suggesting that the more experienced and skilled referees are less susceptible to home-team effects such as crowd support when making decisions. Verf.-Referat