Referee Home Bias in English Premier League

Abstract

Referee bias is thought to contribute to home advantage, especially in soccer. Recent research has shown that sports where referees have power to influence the outcome of the match tend to experience a greater home advantage. Referees' decisions may be influenced by crowds, but little work has been done to examine how referee behavior would change when crowds are not present in stadiums since it was impossible to isolate crowds from stadiums. To analyze how crowds in stadiums influence the decision making of referees, I examine 1,428 English Premier League (EPL) official matches during the seasons 2018/19 through 2021/22, including ghost matches induced by Covid19. The results show that referees are responsible for some of the home advantage in the EPL, meaning there was a clear advantage for the home team over the away team before Covid. But during the Covid phase, the home team's winning rate dropped by ten percent and referees' pressure to make decisions decreased and awarded more yellow cards to the home team than before Covid. I hypothesize that referees respond differently to factors such as pressure and I suggest further research at referees' behavior within the different top European leagues.