Home Advantage In The UEFA Champions League Under The COVID-19 Pandemic

With the rapid development of modern professional football,the research on home advantage is more and more in-depth.This study took advantage of a unique "natural experiment" condition created by the limited conditions for hosting Champions League matches due to COVID-19: empty UEFA Champions League matches in the 2020-2021 season.Home advantage is usually defined as the percentage of points won at home(number of goals scored)to the total number of points won at home and away(total number of goals scored)in a league match.According to this calculation method,50% means that there is no home-court advantage,and the greater the percentage is,the greater the home-court advantage is.Factors influencing home advantage include: crowd support,referee bias,travel fatigue effect,city Derby,ground familiarity,territorial protection awareness,special tactics,team strength and composition,rule factors and psychological factors.Previous research has shown that crowd support and referee bias are major factors in home advantage.The purpose of this study is to explore the effect of empty matches on team performance and referee bias when the home crowd is stripped away.By comparing indicators related to team performance and refereeing bias between the2018-2019 UEFA Champions League and the 2020-2021 UEFA Champions League,the study found that,for team performance,the data clearly show that playing without a home support crowd has a significant negative impact on the home team’s attacking performance.Home advantage depends to a large extent on the presence of the home crowd,which is embodied in: In the 2020-2021 Champions League,the number of goals scored by the home team,the number of shots on goal,the number of positive shots and the number of corner goals decreased significantly.The win rate of the home team decreased by 4.84 percent,the win rate of the visiting team increased by7.16 percent,and the home advantage(HA%)decreased by 7.99 percent.The results reinforce the long-held belief that home advantage is an important factor in improving the home team’s chances of winning a match.In terms of referee bias,in the statistical data,the number of fouls,yellow cards and red cards of the home team in the2018-2019 UEFA Champions League and the 2020-2021 UEFA Champions League did not change significantly,indicating that the referee’s penalty for the home team did not vary depending on the size of the home crowd.But there was a marked reduction in the number of fouls awarded by referees to visiting teams,suggesting that decisions were not only more balanced but even favoured away teams once the noisy home crowd was away.Although referees’ decisions do not affect the outcome as much as a team’s performance does,it is still a material influence.