The health crisis caused by the COVID-19 has changed the daily lives of millions of people worldwide. Football is not away from this paralysis. After several months without matches, the competition returned and some changes were made: the players’ number for each game was extended, and the maximum number of substitutions was increased up to 5. Nevertheless, the biggest news is that the competition started to be held without an audience in the grandstands. What is the effect of playing behind closed doors? Is the field factor less critical when there are no fans pushing home teams?

There is clear scientific evidence that supports the advantage of playing at home for local teams.^1.2 For example, in the five most important European leagues (English Premier League, German Bundesliga, Serie A – Italy, LaLiga – Spain, and Ligue 1 – France), local teams win in 44-46% of matches, and they score between 0.3 and 0.4 goals more than the visitors. The home advantage (the percentage of points scored by home teams over the total points achieved) is 60%.^3,4

The factors that explain this positive effect are diverse. Still, the two most important are the bias of the referees and the stimulating effect of the audience on the players´ behaviour. Lab research has shown how crowd noise causes the referees to erroneously indicate 15% of the fouls in favour of local teams.^5.6 When the background noise is eliminated, the collegiate´s bias disappears. It has also been shown how the extended time of matches is greater than it should be when the team that plays at home is losing by one goal and less when it is winning by the same difference. When the audience pushes, testosterone levels and cortisol increase; in football players who play at home compared to what happens to the opponents. The same effect has been found when official and friendly matches are compared.

According to data from the CIES Football Observatory (report No. 304), the field factor has suffered due to the audience´s absence. The authors of the analysis have studied 63 leagues worldwide where at least 40 games have been played behind closed doors due to the COVID-19 crisis. The games won by local teams have gone from 44.3% to 42.2%, and the goal difference has changed from 0.32 to 0.24. In other words, playing without an audience has reduced the percentage of local victories by 2.1% and the goal difference among opposing teams by 0.08 points. The most significant decline came in the Greek Super League, where home wins have fallen by 15.1%.

On the other hand, the Swiss Super League has seen local victories increase by 8.5%. Home win percentage has dropped in 41 of the 63 leagues studied. According to the data from the web BeSoccer, in the 11 European leagues that have been analysed (Italy, Spain, Germany, England, Austria, Denmark, Russia, Portugal, Turkey, Greece, and Switzerland), playing matches without an audience has caused the following: local victories have decreased by 2.5%, and visitors have increased by 2.15%. In addition, the goals of home teams have fallen by 2.20%. However, goals from visiting teams have risen by 6.79%. Besides, fouls and cards number received by home and visiting teams in matches without an audience has been equaled. For example, local teams were penalised before the stadiums closed in the German Bundesliga with 44.85% (405) of yellow cards and 33% (14) of red cards. After the competition resumption, they received 51.1% (178) and 66% (8), respectively.

In LaLiga, the percentage of home victories, ties, and visiting victories in the 270 matches played before the competition stop in the 2019/2020 season was as follows: 47.7% (129 games), 24.4% (66 games), and 21.7% (75 games), respectively. In the 110 matches held without an audience, the percentage was: 40% (44 games), 28.2% (31 games), and 31.2% (35 games). In other words, the percentage of local victories has fallen by more than 7% and visiting victories have grown by almost 10%. The penalties percentage whistled against local teams decreased by 15.4%, while it has increased by 46% in favour of the visiting teams. The goal number for the local teams went from an average of 1.51 per game to 1.26. For the visiting teams, it went from 1.03 to 1.07. The advantage of being a home team has been reduced by 4.54%. It has gone from 63.17% to 58.63%.

The more academic research that has studied the effect of playing without an audience ultimately suggests that: ¹ (1) it slightly reduced the advantage of playing at home; (2) the impact varies significantly between countries and competitions; (3) the refereeing decisions (fouls and yellow cards) did not benefit the home teams as much; (4) the advantage of playing at home continued to depend heavily on the difference between the teams and the competitive balance of the competition; (5) an adaptation of the performance of the teams seems to be appreciated when they play without an audience. As more games were played behind closed doors, the advantage of playing at home was regained.

References

¹ Lago Peñas, C. & Gómez, M. (2020). El jugador número 12. La ventaja de jugar en casa en el fútbol. Edición de los autores.

² Gómez, M., Pollard, R. & Lago-Peñas, C. (2021). Home Advantage in Sport. Causes and the Effect on Performance. London: Routledge.

³ Pollard, R., & Gómez, M.A. (2014). Components of home advantage in 157 national soccer leagues worldwide. International Journal of Sport and Exercise Psychology, 12, 218-233.

⁴ Sánchez, P.A., García-Calvo, T., Leo, F., Pollard, R., & Gómez, M.A. (2009). An analysis of home advantage in the top two spanish professional football leagues. Perceptual and Motors Skills, 108, 789-797.

⁵ Nevill, AM, Balmer, NJ, & Williams, AM (2002). The influence of crowd noise and experience upon refereeing decisions in football. Psychology of Sport and Exercise, 3(4), 261-272.

⁶ Unkelbach, C., & Memmert, D. (2010). Crowd noise as a cue in referee decisions contributes to the home advantage. Journal of Sport and Exercise Psychology, 32(4), 483-498.