In 2012 economist Tobias Moskowitz and journalist Jon Wertheim demonstrated in his book Scorecasting that in the fact that it was easier to win at home than away there was no other factor more important than the referees. With an exhaustive work of data on different sports, the work exposed that neither elements like the fact of playing in a field that is not the usual, nor the displacements, nor the effect that the public could have on the equipment visitors were comparable to the weight of refereeing in the field factor.
The pandemic has certainly been an experiment in many ways, and the data show that without an audience the referees lose their usual bias in favor of home teams. More than 700 matches have been played since professional football resumed between the Bundesliga, the Premier League, Serie A and the Spanish league, and in all four competitions there has been at least one unprecedented event with data since 2005: Home teams have seen more yellow cards than away teams. No season of any of these leagues since 2005 has ended with a greater number of warnings taught to home teams than to away teams, which has occurred in all four leagues if we take the matches that have been played. since the late spring decay. On average, between 2005 and March 2020, referees showed 16% more yellow cards to away teams than to home teams. Without an audience, the trend has been reversed.
With lighter penalties such as fouls the bias is not as marked, but it has also been reversed in three of the four countries, and has almost equaled in the Bundesliga. With the red cards the picture is less clear: since football resumed, only 123 players have been expelled in total, a sample too small to draw clear conclusions. In Italy there have been more expelled visitors than ever before, but the dynamic in all four leagues has also been to reduce the bias: if between 2005 and March 2020 35% more visitors were expelled than of premises, since then the difference has been reduced to 16%.
It is true that the data by season show how a trend has been drawn in recent years towards favoring fewer and fewer local teams, but the leap that has taken place since March is resounding and could not be explained without the factor of empty stands.
This has undoubtedly been one of the important factors that have contributed to diluting the advantage of playing at home during this period. If between 2005 and the outbreak of the pandemic the home teams gained 59.7% of the points, since March they have gained only 52.3%, and in the case of the Bundesliga this figure has fallen up to 47%. In Germany, visiting teams have gained more points since March than locals.
Beyond the pandemic, the data on arbitration sanctions by country reveals some curious facts about how different arbitrations between leagues are. While in England 866 players have been expelled since 2005, in Spain there have been 1,808, more than double. In the Spanish league is where he is most expelled, followed by Serie A, where in recent years there have been 1,695 players who have not finished the game. Another interesting aspect is how the number of interruptions during matches has been reduced: in all four leagues in the 2005/2006 season, 35 fouls per game were whistled, while in the last three seasons the figure is has located between 24 and 25.