After COVID-19 disrupted football, no more than it disrupted all of society and civilization across the world, and enforced a pause of several months, the games have recently restarted with the German Bundesliga the first of the major leagues to resume play. Games are played without fans, leading to a stark leveling of the home cooking used by teams to gain an advantage on their own territory. Playing at home confers a distinct advantage – everyone knows that. But the restart of football got me thinking about how much of an advantage is there really.
I draw upon a few data sets. I have match results for the Turkish Super Lig back the 1959/60 season, the German Bundesliga from the 1963/64 season, the full set of Premier League fixtures starting in 1992/93, and Spanish La Liga and Champions League results dating back to 2010/11. I have omitted details on the La Liga and UCL because the data set is small – and some fields have odd values that make me doubt the data integrity – but I have included them in the full file linked at the end. I also have events data (goals, bookings, penalties, etc.) for those seasons. Some of the earlier seasons of the Turkish and German leagues have missing data for certain event types so some seasons are omitted in the analyses.
First, I looked at the points advantage that home teams gain. After all, the long-term goal of every club is to accumulate points over the course of a season. I use a simple metric: net points gained per home game, calculated with simple arithmetic by subtracting the average points per game for away teams from the average points per game for home teams. At a very high level, across all of the data sets I looked at, recent trends show that home field confers an advantage of between 0.4 and 0.6 points per game. What is evident – more so in the German and Turkish data sets because of the larger data set – is that the home advantage has decreased over time. But it still exists and is significant.