The introduction of the Video Assistant Referee supports the fairness of the game – An analysis of the home advantage in the German Bundesliga

The introduction of the video assistant referee (VAR) was a landmark in soccer history, yet it is not empirically examined whether the technology contributes to the most supreme value of the game: fair play. Because referees are said to be one driving cause of the home advantage (HA), the aim of this study was to examine whether the HA changed in the German Bundesliga since the implementation of the VAR in the season 2017/18. We examined a total of 2448 games during the four seasons before and after the implementation of the VAR with regards to the game outcomes (i.e., goals and points) as well as indicators of referee bias (i.e., fouls, yellow cards, 2nd yellow cards, red cards, and penalty kicks) for both the home and the away teams. Findings indicate that the VAR influences game outcomes to a fairer degree. Specifically, (i) we found statistical evidence for the HA before, but not after the implementation of the VAR. However, (ii) these results need to be interpreted with caution because direct assessments of the change induced by the introduction of the VAR are not statistically significant. Finally, (iii) with the implementation of the VAR, fewer fouls were committed by both the home and the away team.

Losing the Home Field Advantage When Playing Behind Closed Doors During COVID-19: Change or Chance?

Due to restrictions against the COVID-19 pandemic, spectators were not allowed to attend soccer matches at the end of the 2019/2020 season. Previous studies suggest that the absence of a home crowd changes the home field advantage in terms of match outcomes, offensive performance, and referee decisions. However, because of the small sample sizes, these changes may be random rather than meaningful. To test this, we created 1,000,000 randomized samples from the previous four seasons with the exact same number of matches played behind closed doors in Europe's four most elite soccer leagues at the end of the 2019/2020 season. We found that across countries (Germany, Spain, Italy, and England), performance indices and referee decisions (except red cards) indeed changed to the detriment of the home team beyond the level of chance. However, this overall pattern could be ascribed to specific countries. Most importantly, the proportion of points won by the home teams declined significantly only in Germany, which was accompanied by a meaningful increase in (1) the proportion of goals scored by the away teams and (2) the proportion of yellow cards given to the home teams. We conclude that the home field advantage may indeed be lost when spectators are absent. However, in future studies, more detailed behavioral analyses are needed to determine the robustness and the behavioral determinants of this phenomenon across leagues and countries.