This Monthly Report analyses the evolution of the competitive balance in the group stages of the Champions League since the introduction of the current format in 2003/04. The different indicators analysed illustrate a clear trend towards less balance and more predictability.
The efforts of UEFA to curb this trend through easier access to the group stage for representatives of the countries with the wealthiest leagues have not met with success given the extent of economic gaps between teams, including within these championships. A thorough rethink is needed to preserve a sufficient level of sporting and economic balance both within the competition and in European football.
2. Distribution of points
An initial analysis focuses on the distribution of points at the end of the group stages. The sixteen seasons studied were divided into four groups of four seasons to attenuate the effect of annual variations. This analysis shows that teams at the top of their group have progressively obtained more points and significantly improved their goal difference.
Figure 1: points per match and goal difference of teams at the top of the group, Champions League (2003-2018)
The same analysis for teams at the bottom of the group shows an opposite trend. The points per match achieved by these clubs went from 0.59 between 2003 and 2006 to 0.45 during the last four seasons analysed. The goal difference also deteriorated falling from -6.7 to -9.1 between the first and last periods covered in the study.
Figure 2: points per match and goal difference of teams at the bottom of the group, Champions League (2003-2018)
3. Goal difference
A second analysis to understand the evolution of competitive balance in the Champions League consists of measuring the average goal difference in group stage fixtures. A higher value reflects greater imbalance at match level. This analysis confirms the existence of a constant and progressive drop in competitive balance.
Figure 3: average goal difference for group stage matches, Champions League (2003-2018)
The increase in goal difference at group stage matches level is notably linked to the growth of fixtures which concluded with at least a three goal difference. The percentage of very unbalanced matches has increased from 16.9% during the first four seasons analysed to a new record of 22.9% between 2015 and 2018.
Figure 4: % of group matches with at least a three goal difference, Champions League (2003-2018)
To measure the unpredictability of matches, we have gathered data for the team odds on the betting market since 2004/05. The fifteen seasons selected for this analysis were grouped in three blocks of five. The correlation coefficient between the estimated probabilities and the actual results is a good indicator in determining the ability of the market to predict the outcome of matches. The strong increase observed confirms the findings of greater predictability.
Figure 5: correlation between estimated probabilities and results, Champions League (2004-2018)
The greater predictability can also be read through the increase in the percentage of fixtures where teams that are clear favourites go on to win the match. A threshold of a 60% chance of victory was chosen for this analysis. The findings show that the big favourites win with increasing frequency: in 81.4% of cases at home between 2014 and 2018 (+5.3% in comparison to 2004-2008) and in 74.6% of cases when playing away (+12.1%).
Figure 6: % of matches where the clear favourite wins, Champions League (2004-2018)
In the current context, with the same number of participants, only a better distribution of resources both internationally and nationally would allow for more balance to be brought to the group stages of the Champions League. However, this solution runs into opposition from the financially dominant clubs.
An alternative solution would consist of drastically reducing the number of teams having access to the group stages. Such a change would, however, exclude even more representatives from countries with a less developed football market. This would go against the UEFA’s federative role and would also provoke strong opposition.
Confronted with pressure from multiple fronts, UEFA finds itself in a stalemate. A good compromise would consist of reducing the number of participants in the group stage of the Champions League, while keeping an open system of competition. Contrary to the most recent reform, the compromise would also be to guarantee a greater percentage of revenue for clubs participating in the other European competitions and to reinforce solidarity towards other countries and clubs.
Solidarity could, for example, operate through a meritocratic basis by keeping aside part of the revenues earned from organising the competition for all of the teams having participated in the training of players fielded on a pro rata basis for the number of seasons that they have spent in each club since their earliest days.
This measure could also be applied to non-European teams, where numerous talents are trained. Such a redistributive mechanism would have the great merit of recognising the fundamental role played by a multitude of clubs in developing players who guarantee the high quality spectacle that the major teams produce and from which they derive benefit.
Monthly Report n°42 - February 2019 - Evolution of competitive balance in the Champions League