The impact Covid-19 has had on sport is unprecedented. Events and fixtures have been cancelled or postponed across the globe causing a knock-on effect throughout sport in terms of scheduling, athlete preparation and business. As the world’s biggest sport, football has been at the centre of the postponement saga.

The first reported disruption to football, unsurprisingly, came from China on the 22nd January when a Women’s Olympic qualifying game was relocated from Wuhan to Sydney, Australia. In early March, European leagues began to move games behind closed doors and by the 12th we had seen our last top-level European game as competitions were suspended.

Since then, numerous announcements have been made and hypothetical scenarios have been proposed for the return of football. The financial ramifications and differing objectives of teams, players, leagues, broadcasters and sponsors have all had a role to play. However, it seems there is a growing mood that playing behind closed doors could be a serious consideration. In England and Scotland, the law restricting football being broadcast at 3pm on Saturdays has been lifted clearing the way for games to be shown live on TV at this time for the first time in almost 60 years. This will help leagues complete the season and keep stakeholders as happy as possible in such a situation.

There is no doubt that the atmosphere generated by fans in full stadia provides an integral element to the experience. The recent Champions League games played behind closed doors are a testament to that with players reporting feelings of “sadness and emptiness” following playing in barren arenas. But did it actually influence the game and if the remainder of this season’s Premier League games are to be played behind closed doors, will the removal of the “12th man” impact on players’ performance?

During the 1988/89 US college basketball season, a measles outbreak caused two teams (Siena and Hartford) to play behind closed doors for 11 games. This gave researchers a rare opportunity to examine the impact of an empty arena on player performance. Perhaps counter-intuitively, when performance statistics were analysed it was actually found that both teams registered an improvement during this period (Moore and Brylinsky 1993). It must be said that the authors acknowledged a number of potential flaws in the research, including the statistical tests used and the lack of control for the quality of the opposition.

Still, this does fit a narrative often heard in professional sports, when the pressure of the home and the expectant crowd is removed, players are free to play their own games and can focus on executing their skills and the tactics of the team without the additional complication of outside influences such as a hostile home crowd.

Other research cited in a seminal paper examining home advantage by Courneya and Carron (1992) revealed that home games in front of a supportive crowd lead to greater player confidence. Greater confidence increases belief in a positive outcome and therefore players play better as part of a self-fulfilling prophecy. Playing better can manifest itself in greater effort, more communication with teammates or increased assertion to name but a few. However, a major body of research has emerged suggesting the influence of the 12th man, rather than impacting player performance directly, is actually swaying the decisions of referees to favour the home team.

This is an unconscious response from the officials but the impact of the crowd shows consistently that disciplinary sanctions (yellow and red cars), as well as the amount of stoppage time added to the end of games, favours the home team. One such analysis across UEFA Champions and Europa League games showed that away teams receive 25% more yellow cards than home teams (Goumas 2014).

At the elite level of the game, it might only take a few minor decisions to go in favour of the home team to have a material impact on the match outcome. If away team players have received, or feel they are more likely to receive a booking, it could temper their play and produce decreases in effort and assertion in certain situations. A deeper analysis of the data from Goumas’ 2014 study shows that a relationship exists between crowd density (dividing crowd size by stadium capacity) and the unconscious bias of referees. When crowds were at less than 25% capacity, no bias was detected but as crowd density increased to 50% and then up to 100% capacity away team bookings increased by 13% and 35% respectively.

Football stakeholders are desperate for there to be a conclusion to this year’s competition. The league, broadcasters, teams and sponsors must find a way to recover some revenue. For the fans, the opportunity that a return of football will bring is a much-needed break from the ‘new normal’. For some sponsors, behind closed doors may even increase their exposure as the potential ‘captive audience’ could be even larger than usual, and with the rules that limit drinking at football not applying in our living rooms, there may even be a retail bounce normally associated with a major summer tournament.

If the remainder of the football season is allowed to continue behind closed doors, it will bring some good news for the business and fans of football. But what impact will that have on player performance? The evidence suggests that once the adjustment to behind closed doors is overcome, direct player performance may not suffer, and could even improve. However, with no fans in stadia to influence refereeing decisions, any previous advantage gained from playing in front of a capacity home crowd will disappear. Can sponsors step in and help fans feel part of the team in other ways or unfortunately, without the option of going to the ground, will supporters be left unable to affect the game and have to make do with waving their imaginary yellow cards from the sofa...

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