The 2020 Nations League group stages concluded this week. The tournament was founded in 2018 and was devised to eliminate the non-competitive friendlies that often faced the ire of European football clubs. It also offered a more balanced competitive format for an international European football competition.
How has balance changed over the two Nations Leagues that have taken place? One way of considering this is to look at bookmaker odds for the competition. Although the difference in betting odds between a home and away win does not control for draw probabilities, this is a quick and easy way to give some insight into balance.
Controlling for the bookies over-round, the average difference in probabilities for a current Nations League match was 0.31. The median was 0.29. For the 2018 Nations League there was a higher mean and median (0.37 and 0.35, respectively). To put this in perspective, the mean difference in odds for Euro 2020 match was 0.55 (with a median of 0.57). For those not familiar with the UEFA international qualification groups for the World Cup and Euros, these are notoriously unbalanced.
On first glance, the competition may have become more balanced. Although the comparison is not perfect - the most recent competition was behind closed doors, a factor which would likely impact odds.