Research - 08.02.2024 - 14:51 

HSG study shows: Pressure from top football clubs on referees can lead to distortions

Are top clubs in European football favoured by referees? Is there bias in their decisions on the pitch? Two recent studies by HSG Professor Francesco Audrino deal with these questions.

Accusations of unfairness in football always seem to creep into conversations about the sport. Recently, there have been allegations charging that top European football clubs violated fairness rules in financial reporting (Juventus, Manchester City) or corruption (Barcelona): These are only few recent cases of a sequence of scandals that involved top European clubs.

The ultimate question that is widely discussed among fans, journalists, and football experts is whether this type of behaviour ultimately leads to them receiving preferential treatment from match officials directly (corruption) or indirectly (pressure due to strong financial power). An interview with HSG professor Francesco Audrino.


Professor Audrino, what caused you to look into referee bias?

As a football fan myself, I am acutely aware that there has always been accusations of referee bias. I wanted to see if the data supported this assumption. Specifically, I gathered statistics to see whether or not the strongest and most popular European football clubs get preferential treatment from match officials. 

For this study, Do match officials give preferential treatment to the strongest football teams?, I analysed data from four teams which were chosen because they are good examples of what we were looking for and they provided me with a sufficient amount of data so that I could perform a reliable statistical analysis. I looked at two Italian Serie A clubs Inter and Juventus, as well as German Bundesliga team Borussia Dortmund and English Premiere League team Manchester United. All four of these clubs experienced a prolonged period of strong football results followed by a losing streak in the years 2006-2016. This allowed me to compare referees’ treatment for the same club in two different situations.

What were your findings?

Surprisingly, at least to me, the analysis did not confirm the general opinion among sports enthusiasts that the strongest clubs receive preferential treatment from match officials. The only club for which I found a significant bias is Juventus. During its winning streak, more yellow cards and total booking points (an aggregated measure of yellow and red cards) were given to Juventus’ opponents. 

How strong was the bias?

The bias was not only statistically significant but also sizable: On average, Juventus opponents received one yellow card more and 35% more booking points per match.

Your second paper also looked at bias in football?

Yes, that is correct. For this one, Strongest Team Favoritism in European National Football: Myth or Reality?, I extended the analysis to the strongest European clubs of the five major leagues comparing top teams to other teams. The study aims to investigate if referees' decisions, such as giving sanctions given to players, are influ-enced by external pressures. Part of my hypothesis was also to see whether things like popularity, the media, public opinion carried over into the match. 

When addressing bias, are we talking about conscious bias or also unconscious bias?

I imagine that the overwhelming majority of match officials are trying to do their jobs properly and without bias… so by looking at the external factors I considered, I would believe that the biases, if they exist would be unconscious.

And your findings?

While I would state that further research is essential for definitive conclusions, this study highlights the existence of bias among officials. There is clear evidence that supports the existence of off-the-pitch influence in the top leagues in Italy, Germany, England, and Spain.

Referees in games involving national league teams where one of them is a Champions League club tend to award more sanctions (up to 12% more yellow cards) to these top teams' opponents. What I found somewhat shocking is that the size of the bias is of the same magnitude and complementary to the home bias that already and is widely discussed in studies. When adding up these two sources of bias, the distortion in referees’ decisions start to become a factor that has an in-fluence in the final results of the matches.

What can be done about this?

I think the first step is recognizing it. Recognizing bias does not mean that the refer-ees are corrupt. Acknowledging the potential existence of bias can take us to a place where it can be addressed and can ensure that we maintain a fair competitive environment. Otherwise, it would be very hard for clubs that do not constantly qualify for the Champions League to compete and grow.

Both papers Do match officials give preferential treatment to the strongest football teams? and Strongest Team Favoritism in European National Football: Myth or Reality? by Prof. Francisco Audrino are avalaible online. 

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