Beating Thy Neighbor : Derby Effects in German Professional Soccer

Derbies between two teams from the same city or region catch more public attention than "normal'' soccer matches. Terms such as "Old Firm" (Rangers vs. Celtic), "Merseyside" (Liverpool FC vs. Everton FC), "Superclásico'' (Boca Juniors vs. River Plate), and "Revierderby" (Dortmund vs. Schalke) are well-known even to people outside their respective countries of origin. Using data from the German Bundesliga from 1999 to 2009, we test whether derbies differ from other soccer matches with respect to the number of goals, match results, the number of scoring chances for both teams, and referee evaluations. We find some evidence for derby effects, for example, the home advantage of the home team with respect to the number of goals scored, the match result and the attempts vanishes whenever the match is a derby. With respect to the evaluation of the referee, we find evidence that sending-offs are associated with a lower referee performance grade in derbies. We conclude that referees make a greater number of wrong decisions in derbies with regard to sending-offs. However, when considering the overall marginal effects of a derby on our dependent variables, we find no significant differences between derbies and "normal" matches