Is home-field advantage driven by the fans? Evidence from across the ocean

Some have claimed that referee and home-field bias in football (American soccer) have been impacted by the fans at the match. When fans are hostile, the threat referees feel to their health and well-being influences their ability to call a fair match. We analyse two leagues with differing fan types: one 'hostile' league (Germany's Bundesliga) and one league perceived as 'peaceful' (America's Major League Soccer). Although there is a strong home-field bias inherent in football, we find evidence that part of the bias is due to the prospect of fan violence.