Home team's advantage reduced without crowd support after the COVID-19 outbreak

Historically, fan attendance at sporting events has always been considered an advantage for the home team. The level of fan attendance at soccer matches was evaluated as a decisive effect to modify the performance of the home teams in the most important soccer leagues around the world. We exploit the effects of the absence of spectators driven by COVID-19 pandemic mitigation policies. We find that the advantage of the home field, measured by the proportion of wins and also by the numbers of goals and points scored, is remarkable in many leagues. We performed comparative hypothesis tests with eight of the world's top soccer leagues, confirming a decrease in the probability of a home win, greatly affecting the matches' outcomes.