Crowd Control: Why Economists Love Empty Stadiums

The coronavirus pandemic has provided countless opportunities for behavioral scientists to conduct and publish research about human behavior. While much of this work has been related to the domain of health, there have also been many studies in other areas affected directly and indirectly by the global crisis. One of these is soccer. (Even if you’re like me and you’re not normally into sports, I would encourage you to have a look at some behavioral research in this area, as it has produced some very interesting data for social and behavioral scientists over the years, including economists.)

Since the start of the COVID-19 pandemic in 2020, soccer matches in Europe have been held without spectators in the stadiums. Data from soccer games can, therefore, provide perfect conditions for a natural experiment about the extent to which the absence of crowds has affected performance on the pitch.

The economist Vincenzo Scoppa analyzed data from five major European soccer leagues (England, Italy, Portugal, Germany, and Spain) and compared matches played with crowd support to matches played without the crowd. Past research on social pressure has found it to significantly affect people’s willingness to give to charity, workers’ productivity, and voting in elections, to name just a few. Does the absence of social pressure created by spectators affect soccer players’ performance and referees’ decisions?

Scoppa’s analysis found that crowd support generally creates a home advantage for teams that is evident in different aspects of performance (points, goals, etc.), but this advantage is almost halved when matches are played behind closed doors.

In soccer, teams are awarded 3 points for a win, 1 point for a draw, and 0 points for a loss. The data show that home teams gain about 0.50 more points when spectators are present (1.61 for the home team vs. 1.11 for the away team, on average). When the crowd is absent, the home advantage reduces to about 0.28 points. Similarly, pre-pandemic matches have a 0.35 difference in goals between the home and away teams (1.49 vs. 1.14). In matches without spectators, this difference is almost halved from 0.35 to 0.20.

Similar results are also seen in other team performance indicators, such as shots and corner kicks.

An even more striking behavioral result emerges when we look at the decisions taken by referees, who are supposed to be impartial umpires. Scoppa analyzed a range of variables, including decisions of fouls. These decisions tend to be in favor of home teams when stadiums are filled with crowds but become significantly more balanced without spectators influencing referees. This remains significant even when the effect of team performance is controlled for in the analysis.

Past research has pointed to crowd support, travel fatigue, and stadium familiarity as factors that may explain the home advantage. Scoppa’s research suggests that the social pressure created by stadium spectators (in terms of both crowd support and referee bias) may explain about half of the home advantage.