UEFA Euro 2020: Was it balanced and did home advantage play its part?
Before the start of UEFA Euro 2020, I discussed whether the competition was going to be balanced under the new tournament layout and if teams playing at home were going to do better.
I was confident the event would be balanced, while the teams playing at home would have an advantage.
Now that we are nearing the end of the tournament, it is time to check whether I was right or wrong and whether England have a chance to win this year’s Euros.
Competitive balance
A way to assess whether the tournament is competitively balanced or not is to calculate its so-called intra-match competitive balance. This is the percentage of game time with a difference of no more than one goal between the two teams in each match, and means that any time a team can take the lead or equalise.
In my previous research on men’s football, I identified that a percentage between 85% and 90% (between 76.5 and 81 minutes out of the 90 minutes of a football match) is what can be expected for a balanced tournament. UEFA Euro 2020 is within this range.
Right now, before the semi-finals and final, the percentage is 86.6% for the 48 matches that already happened meaning Euro 2020 has been a balanced tournament.
In the group stage, the groups with the most balanced matches were Groups F (France, Germany, Hungary and Portugal; 92.2%), E (Poland, Slovakia, Spain and Sweden; 91.3%) and D (Croatia, Czech Republic, England and Scotland; 90.6%).
The other groups were less balanced, with 83.9% for Group B (Belgium, Denmark, Finland and Russia), 80.7% for Group C (Austria, the Netherlands, North Macedonia and Ukraine) and 77.8% for Group A (Italy, Switzerland, Turkey and Wales).
The teams with the most balanced matches during the group stage were England, France and Wales (100%). The teams with the least balanced matches were Switzerland (64.4%); Turkey (69.6%); the Netherlands (70.4%); and Russia (71.1%).
Home advantage
Out of the 24 teams in the tournament, nine teams played at home at some point during the group stage and six of these nine teams (67%) qualified for the round of 16, against only 10 of the 23 other teams (43.5%).
The four teams qualified for the semi-finals (Denmark, England, Italy and Spain) have all played at home during the group stage, with England having also played at home in the round of 16 against Germany and will play at home again in its semi-final against Denmark (then again in the final if England wins against Denmark).
Overall it seems safe to say that the teams playing at home did better and I suspect the existence of a home advantage effect. However, it is also important to remember that each team has their respective strengths and there is a need to control for this in order to identify whether the teams playing at home did better because of home advantage, because they are the strongest, or because of both reasons.
I have run a model to explain the difference in score between both teams in all 48 matches already played in the competition based on home advantage and the strengths of the teams. Surprisingly, it seems that home advantage has overall had a negative impact and cost almost one goal for a team playing at home.
However, this impact is not significant in statistical terms; in other words, we cannot be confident that it automatically applies to all teams playing at home in the tournament – good news for England for its semi-final (and maybe final).
The model also shows that once home advantage is controlled for, the best team is England with an advantage of 0.66 goal over Denmark (who comes out second best) and almost one goal over Italy (third best). The other semi-finalist, Spain, comes only as eighth best after Belgium, Czech Republic, the Netherlands and Croatia, although it is more or less as strong as the latter according to the model.
According to the model, the weakest team was Slovakia, followed by Turkey, North Macedonia, Poland and, to a lower extent, Sweden and Ukraine, despite them qualifying respectively for the round of 16 and quarter-finals.
But can England win?
For the match played tonight, Italy is supposed to win by one goal against Spain and, as such, to qualify for the final. But what about England?
England qualifying for the final and winning the tournament seems to rely on a trade-off between the team being the strongest according to our model and a potential home disadvantage. Taking into account the latter, England underperformed against Scotland (draw instead of win by one goal), performed as expected against Croatia, Czech Republic and Ukraine, and over performed against Germany (win by two instead of one goal).
According to my model, England is supposed to draw against Denmark, then, if qualified for the final, to draw again against Italy, or alternatively win by one goal over Spain.
In the end, the semi-finals and final are supposed to be balanced with, hopefully, a final win for England on Sunday.
