The advantage of playing games at home in most sports is widely accepted as fact, but is this actually the case? Is playing at home an advantage in soccer and if so, how do we measure that advantage? In this article, Dominic Cortis shares his thoughts on home team advantage in soccer.
Most mathematical models applied to predicting goals utilise different parameters depending on whether the team is playing home or away. For example, different defence and attack strength values are used in a basic Poisson betting model.
Home team advantage (or home field advantage) is visible in the English Premier League (EPL), with 135 home wins occurring in the 2016/17 English Premier League in contrast with 92 away wins with the average score being 1.60 to 1.20.
Often abbreviated to HFA, refers to the perceived advantages enjoyed by the home team.
However, as we have discussed in the past when looking at how to build a betting model, the metric selected does have an effect. One can argue that the median score is 1-1, hence there is no evidence of a difference.
Why you should consider goal difference
Marek and Vavra have recently published a research project on home team advantage. In their analysis of home team advantage in the EPL; they investigated whether there is evidence of teams performing better at home by considering the goal difference rather than just the outcome.
That is if a team lost 1-0 at home but 4-0 away, it is implying that the team has some sort of home advantage, despite losing both matches. They could not find a particular trend but their paper - Home Team Advantage in English Premier League - provides a very interesting read.
Whilst the aforementioned study offers great insight in terms of home team advantage as a general concept, it also analyses how it benefits individual teams. Liverpool is one example that stands out due to a steady decline in home team advantage of late, compared to Arsenal’s home team advantage, which appears to have been very erratic over the same period.
What contributes to home team advantage?
There is always a level of subjectivity when applying models, hence one needs to consider the possible factors for why home team advantage might exist.
Marek and Vavra point out that last season Swansea and Newcastle showed evidence of a home team advantage. With Swansea being in Wales and Newcastle in the North East of England, it could be said that distance travelled is one factor that should be considered.
Bettors will often consider the impact distance travelled has in the NFL where teams can travel over 2,000 miles for a game (the biggest distance between two Premier League grounds this season - Newcastle and Swansea - is 354 miles). However, distance travelled can still arguably affect the propensity to concede goals and the ability to score in soccer - as this study by Oberhofer, Philippovich and Winner shows.
Outside of domestic competitions, teams will have to travel greater distances for European competitions like the Champions League and Europa League. Given that teams have to travel to and from these games in a short period of time, home team advantage could be more pronounced both in away European fixtures and away fixtures upon return from a European fixture.
Another factor that contributes to home team advantage could be the size of crowds. Whether the fans act as the “12th man” on the pitch is still debatable, particularly when teams like West Ham United and Tottenham Hotspur have increased their capacity with new stadia but still suffered a downturn in performance.
The determinants of any advantage in playing at home can be endless. Recent research into soccer performance - conducted by Alex Krumer and Michael Lechner - has found evidence that home advantage disappears in mid-week German Bundesliga matches.
Additionally, Nevill, Newell and Gale found that home teams benefit more from having opposition players sent off as well as being awarded more penalties. In their recent study in the Journal of Sports Sciences, they ask whether it is the case of actual fouls or perceived fouls - that is, do large crowds provoke away players into more reckless behaviour or do they affect the referee (or both).
A presentation at the last Math Sport International Conference (June 2017) implied that it may be the case of bad refereeing decisions as more such decisions are upturned later following appeal.
I am also very interested to see whether the crowd’s effect is on the home team to score more or less goals, that is whether the intensity change varies depending whether the home or away team scores or concedes. This might mean evaluating whether there are any differences in the timing of the first goal between home and away matches.
If anyone out there is interested in pursuing this academically, please do contact me.