Abstract
The phenomenon of the home advantage is attributed to a variety of causes, including referee biases in many sports. At this, among others, Garicano (2004), Sutter and Kocher (2005), and Dohmen (2009) found referees granting more injury time when the home team finds itself one goal behind compared to a one-goal lead at the end of the regular match time.
In our study, we primarily seek to enforce evidence for this bias, based on actual data of the German Premier Soccer league, including the seasons 2000/01 until 2010/11. We analyzed if the bias is changing in time - e.g. due to a spread of information on this topic – and found an average bias of M = 18 sec. (t(1233) = -4.789, p < .001,d = 0.27), smaller e.g., than Sutter & Kocher (2005). We did not find seasonal changes. We further raise the (up to now neglected) question if the home team in soccer is really capable to benefit of the (small) increase of injury time. Surprisingly, we found in the absolute amount of point changes that the guest teams gained a few more points than the home team. Yet, home teams lie behind far less often and no team turns out to be relatively more successful ( ?²(1, N=1240) = .253, p = .615). We also compare the results with the dynamics in regular match time to get a reasonable standard of comparison. It can be concluded that there is a very small injury time bias in the German Premier league, but the home team advantage is not caused by this biased referees decision.
