It is well known that sporting teams win more often playing at home than away, but the question of why has inspired much research. At least for European football, a new study reveals several factors that provide a benefit, but the most important is altitude. So Swiss teams really have no excuse.
In some sports, it is easy to see why playing at home would offer benefits. Soil and climate affect the bounce of a cricket pitch, so it's hardly surprising people who have spent their lives adapting to particular conditions do better there. It's not so obvious why basketball players, for example, with identical court dimensions would find games on the road more challenging.
Nevertheless, the stats clearly reveal home-ground, or court, advantage remains. To explain why, Dr Nils Van Damme and Professor Stijn Baert of Ghent University analyzed 2012 games from the UEFA Champions and Europa Leagues. With 47 percent won by the home team, 29 percent away, and 24 percent draws there's no doubt it's better to be on familiar turf, but the authors wanted to know what conditions enhanced or diminished the size of the phenomenon.
Fans will be pleased to know their cheering makes a difference; as many previous studies have shown, large partisan crowds make wins more likely. However, the biggest benefit came from being based in a high-altitude city and playing opponents from sea level. “Every additional 100 meters [330 feet] above sea level is associated with (i) an increase in the goal difference by 0.050 goals (p = 0.006), (ii) an increase in the chance of a victory by 1.1 percentage points (p = 0.014), and (iii) an increase in points by 0.032 (p = 0.008) for the home team,” van Damme and Baert report in Economics.
The benefit only goes one way, however; flatland teams don't get a head start when visited from the mountains.
It takes 5,000 screaming fans to equal the benefit from being the height of a 30-story building further into the sky than the competitors.
Other factors the pair investigated, such as how far (horizontally) the away team had to travel, produced no statistically significant effect, although it is possible a larger sample size would have changed this. The authors also considered factors such as climatic and cultural differences between the venue and the away team's origins, but the only one that seemed to matter was being richer than the visitors.
Although reduced oxygen at high altitude is well known to affect new arrivals' performance, multifactorial analysis like this is susceptible to decisions about what gets left out. Perhaps academics from the coastal plane of one of the world's lowest-lying countries were subtly influenced by a desire to emphasize sea-level dwellers' disadvantages. Only replication will tell.