Modelling home advantage in the Summer Olympic Games.

Home advantage in team games is well proven and the influence of the crowd upon officials' decisions has been identified as a plausible cause. The aim of this study was to assess the significance of home advantage for five event groups selected from the Summer Olympic Games between 1896 and 1996, and put home advantage in team games in context with other sports. The five event groups were athletics and weightlifting (predominantly objectively judged), boxing and gymnastics (predominantly subjectively judged) and team games (involving subjective decisions). The proportion of points won was analysed as a binomial response variable using generalized linear interactive modelling. Preliminary exploration of the data highlighted the need to control for the proportion of competitors entered and to split the analysis pre- and post-war. Highly significant home advantage was found in event groups that were either subjectively judged or rely on subjective decisions. In contrast, little or no home advantage (and even away advantage) was observed for the two objectively judged groups. Officiating system was vital to both the existence and extent of home advantage. Our findings suggest that crowd noise has a greater influence upon officials' decisions than players' performances, as events with greater officiating input enjoyed significantly greater home advantage.