What a difference a crowd makes!

Analysing the impact of VAR and Covid-19 on home advantage across the big five European leagues

Fans returning to sporting events including top flight football in England this past weekend has been a huge boost to national morale - and also the beginnings of a return to normality for club finances and crowd support. With this hopefully unique experiment of top-flight football played in empty stadiums coming to an end, we now have an opportunity to analyse what difference a crowd makes.

To get the big picture, we’ve looked at all games played since the start of the 2015/16 season across all five major European leagues (England’s Premier League, France’s Ligue 1, Germany’s Bundesliga, Italy’s Serie A and Spain’s La Liga). This gives us a large dataset with strong statistical significance: 8,642 games pre-Covid, plus 898 post-Covid in empty or near-empty stadiums (408 games finishing off the 2019/20 season and 490 games in the 2020/21 season so far).

To analyse what’s happened, we’ve looked at three key metrics for each season (and each part season for 2019/20, pre and post the Covid break):

• Average home points advantage per game (difference between the average points gained by the home side and the average points gained by the away side)
• Average home goals per game
• Average away goals per game

So what do the stats show?

The picture is pretty clear: across Europe home advantage has largely disappeared when there are no fans in the stadium (the average home advantage down from 0.48 to just 0.10 points per game). And the prime reason for this is that away teams are scoring more goals when the ground is empty (average up from 1.19 to 1.38 per game), whereas home teams continue to score at broadly the same rate (1.55 down marginally to 1.52).

Looking more closely, season by season, and splitting the post-Covid experience between the final part of the 2019/20 season and the current 2020/21 season, the average home advantage was very stable through 2015/16 to the first part of the 2019/20 season at just over 0.4 points per game (except for one outlier season 2016/17 when it increased to around 0.6 points per game, mainly as a result of home advantage being more prominent in the Premier League, Serie A and Ligue 1). The fall off in home advantage due to empty stadiums was substantial once the 2019/20 season restarted, and has become more established in the current season where, to all intents, it has on average disappeared across all the 5 leagues.

What’s behind this? One theory has been that the introduction of VAR technology could have reduced home advantage because referees may be swayed by crowd reactions to unconsciously favour the home side, particularly when making key decisions in marginal situations such as offside and penalty kicks.

So we’ve also looked at the impact of VAR in isolation, by investigating what happened in games prior to Covid. VAR was introduced at different times across Europe, in 2017/18 for the Bundesliga in Germany and Serie A in Italy, 2018/19 for La Liga in Spain and Ligue 1 in France, and not until 2019/20 for the Premier League in England. Overall 3,470 (40%) of the 8,642 pre-Covid games dating back to the 2015/16 season were played with VAR, and 60% without. The stats for these games, along with post-Covid, show that:

This shows that the introduction of VAR has had a small but material dampening on home advantage, both by reducing slightly the average number of home goals and by increasing the average number of away goals. Both small differences - probably in line with what may have been anticipated when VAR was introduced – but in combination resulting in a 14% reduction in home advantage from 0.51 to 0.44 points per game. However, the impact of VAR has proven to be far less significant than the absence of crowds during the pandemic.

The impact of empty stadiums appears effectively to have been to allow away sides the freedom to be more adventurous, increasing their average goals per game by 15% from 1.20 to 1.38 – while making very little difference to home side goalscoring levels.

How does this differ across Europe?

We looked at each of the five leagues individually as well as in a group, and they have all showed much the same pattern of a sharp fall in home advantage (as measured by average home points difference), but there have been some interesting regional variations.

England, Premier League – a slow starter

Premier League teams took much longer than the rest of Europe to adapt to the new post-Covid environment. Indeed, during the 92 games that completed the 2019/20 season after football restarted in July, there was no discernible empty-stadium effect, with 43 home wins against 29 away wins, and a home points advantage of 0.46 per game. But since the 2020/21 season commenced, away teams have really taken the initiative, winning 43 of the 98 games (prior to crowds returning), compared with 36 home wins, giving an away team points advantage of 0.21 points per game. It’s early days yet, but the first weekend with limited crowds back is following a similar pattern.

Germany, Bundesliga – a fast adopter

The Bundesliga was the opposite of the Premier League, with away teams reacting immediately to the absence of crowds and dominating the end of the 2019/20 season after football restarted. Away sides won 37 of these 82 games, compared with 26 home victories, with an away team points advantage of a massive 0.4 points per game. This season, however, parity has been largely restored, with 26 home wins, 27 away victories and 28 draws (the only season we looked at across all five leagues when draws have outnumbered both home and away victories).

Italy, Serie A, and Spain, La Liga – one a goal feast, the other a goal famine

Serie A and La Liga both had similar levels of reduction in home advantage due to Covid, with it not being eliminated but much reduced, to around 0.2 points per game. However, they have experienced empty stadiums in remarkably different ways in terms of goal-scoring levels.

Serie A continued its transformation from its old stereotypical catenaccio defence-dominated football to become now the highest scoring major league in Europe, taking over the mantle post-Covid from Germany. Maybe players in Italy have felt more relaxed without crowd pressure, and able play a more expansive game taking more risks – Italy being the only country in the big 5 where both home and away teams are scoring more goals post-Covid.

In contrast, Spain has been the only one of the big 5 leagues to experience an overall reduction in goal-scoring following the Covid-break to become by some distance the lowest scoring big league now. Perhaps a continuation of the Atletico Madrid effect, which has seen year on year falls in average goals per game in Spain every year since the 2016/17 season – Atletico showing other teams in Spain that strong organised defence may be the best way of competing successfully with the goal-hungry powerhouses of Real Madrid and Barcelona.

What happens next?

We expect we’ll need to wait at least a few months more until full stadiums are considered safe – we’re sure that all football fans are similar to us in hoping that we see full stadiums at the delayed Men’s European Championships.

We’ll be monitoring closely the impact of crowds returning to see if home advantage returns to similar levels as before Covid. It will be fascinating to see how things develop, for example will away teams retain the confidence to continue scoring at the increased rates we’ve seen since the Covid break and will changes in goalscoring patterns persist into the era of restricted and then full crowd sizes.

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