Do high altitude soccer teams have an unfair home advantage? Ask Brazilian club Flamengo, which threatened to boycott high altitude matches after its players suffered from splitting headaches and exhaustion during a 2007 match against Bolivian club Real Potosi. Real Potosi plays at 3,800 meters (12,500 feet), and Bolivia, Ecuador, and Colombia all host national team matches above 2,500 meters (8,200 feet). Bolivia famously dismantled Brazil 2-0 in 1993 and embarrassed Argentina 6-1 in 2009 at 3,600 meters (12,000 feet) in La Paz, Bolivia.
FIFA responded to the Flamengo debacle by banning official matches above 2,500 meters (8,200 feet), unless the away team had time to acclimatize. The uproar was immediate, especially from Bolivian president Evo Morales. The South American soccer federation CONMEBOL turned up the pressure, and FIFA suspended the ban in May 2008.
Despite the hype, does altitude actually matter? I would undoubtedly struggle in a match above 2,500 meters (8,200 feet), but top class athletes might not. Patrick McSharry at the University of Oxford analyzed South American national team matches based on the away team’s altitude change. He found that teams traveling to lower altitude suffer the most. However, Bolivia, Ecuador, and Colombia – traditionally weaker teams – are the ones doing the descending. It’s likely that these findings reflect team quality differences rather than altitude change.
I came at the problem from another angle. Bolivia, Colombia, and Ecuador don’t always host at high altitude. Bolivia often plays matches in Santa Cruz at 400 meters (1,300 feet), and Ecuador and Colombia play matches in Guayaquil and Barranquilla, respectively (near sea level). I compared matches between the same two teams but hosted at different altitudes. For example, I asked whether Brazil plays worse against Bolivia in La Paz than in Santa Cruz.
I find that altitude matters a lot. Averaging across all match-up comparisons, Bolivia’s winning percentage increases by 45 points when teams travel up to La Paz, and Ecuador gets a 29 percentage point altitude boost in Quito. However, a puzzle remains: Bogota, Colombia is only 250 meters (800 feet) lower than Quito, Ecuador, yet Colombia’s winning percentage drops 20 points on average in Bogota.
Maybe 250 meters (800 feet) is enough to make a difference. Or, maybe Colombia picks Bogota for its Brazil games only when Brazil is really good (for example). In that case the supposed “altitude effects” could be explained by team quality differences again (even though I compare matches between the same two teams). I have a few ideas to reconcile the findings for Colombia and Ecuador, but I doubt that I will completely reverse the Colombia results.
FIFA isn’t planning to reinstate an altitude ban, even though Bolivia appears to have quite an advantage. Personally, I think that altitude is no different from temperature, humidity, or smog, which also contribute to home advantages. Without clear evidence that altitude is dangerous for players’ health, an altitude restriction seems unfair. In the meantime, teams headed to Bolivia should arrive early and keep some oxygen on hand!
