A complete season with attendance restrictions confirms the relevant contribution of spectators to home advantage and referee bias in association football

Abstract

Background Due to the unfortunate pandemic situation, the phenomena of home advantage and referee bias in sports have recently received a particular research attention, especially in association football. In this regard, several studies were conducted on the last portion of the 2019–20 season: the majority of them suggests a reduction—but not the elimination—of the two phenomena, with some exceptions in which no reduction was found or, at the other extreme, the phenomena were not observed at all. Methods The continuation of the pandemic made it possible to replicate the previous studies considering the complete 2020–21 season, thus with the important added value of having a fully balanced home/away schedule—and a higher number of matches—in the various leagues. In particular, the sample of the present study consisted of 3,898 matches from the first and second divisions of the UEFA top five ranked countries, that is, England, Spain, Italy, Germany, and France. For the home advantage, the following variables were examined: distribution of matches outcomes and home advantage for points (also for previous seasons from the 2014–15 one); ball possession; total shots; shots on goal; and corner kicks. Instead, for he referee bias, the following variables were examined: fouls; yellow cards; red cards; penalty kicks; and extra time. Chi-square tests were used to compare the distribution of matches outcomes, and t-tests to compare home vs. away data for the other variables in the 2020–21 season; Bayesian and equivalence analyses were also conducted. Results The main results are as follows: (a) the distribution of matches outcomes in the 2020–21 season was significantly different from that of the last five complete seasons with spectators (Chi-square = 37.42, df = 2, p < 0.001), with fewer home victories and more away victories; the resulting values of the home advantage for points were 54.95% for the 2020–21 season, and 59.36% for the previous seasons; (b) for the other home advantage variables, a statistically significant overall advantage for the home team emerged; nevertheless, the strength of the differences between home and away teams was generally small (0.09 < Cohen’s d < 0.17), and the corresponding means can be considered statistically equivalent for all variables but the total shots; (c) no statistically significant differences emerged between home and away teams for any of the referee bias variables. Discussion These findings demonstrate that the absence of spectators significantly reduced the home advantage compared to previous seasons with spectators. A slight home advantage persisted in the 2020–21 season, probably due to other factors, namely, learning and travel, according to the model by Courneya & Carron (1992). Conversely, the referee bias was not observed, suggesting that it mainly derives from the pressure normally exerted by spectators.

How the 12th Man Influences Football Matches: The Role of Fans and Referees in the Home Advantage Phenomenon

“…In addition, comparing spectator and ghost play seasons, HA scores were higher for spectator seasons (59.4%) than for ghost play seasons (57.0%). This result is like findings from Sors et al (2022a) (58.5% with spectator vs. 54.75% without spectators) and Dellagrana et al (2023) (66.6% with spectator vs. 57.2% without spectators).…”

Exploring the impact of the COVID-19 pandemic in Euroleague Basketball

“…While some studies showed that the HA did not completely disappear in empty stadiums (Wunderlich et al, 2021), other research on the influence of absolute spectator numbers (Moore and Brylinsky, 1993), stadium occupancy (Agnew and Carron, 1994), or noise levels (Salminen, 1993) have shown that spectators do not directly (or only to a very limited extent) take effect on the HA. More recently, studies showed that in certain leagues, the HA totally disappeared in home games without spectators (Fischer and Haucap, 2020), while others presented a lesser HA magnitude (Sors et al, 2022). However, when considering the basketball game, the crowd support seems to have an important effect on team performance.…”

Home Advantage and its Influencing Factors in FIFA World Cup Asian Qualification

“…Admittedly, this has provided the opportunity to examine whether fans are an important influence on the HA of football matches. An analysis of all “ghost matches” in the 2020-21 season in the top five national leagues of UEFA’s first and second divisions found that HA was significantly reduced in the absence of spectators compared to the season with spectators, while the absence of significant differences in referee bias was considered to be related to the absence of spectators (Sors et al, 2022a). Also using the “ghost matches” during the epidemic as material, Leitner et al (2022) conducted a systematic literature review of the importance of football fans based on 21 empirical studies, showing that HA declined during empty games, mainly due to a reduction in referee bias and a lack of emotional support for teams, thus validating the importance of fans for team success.…”