The Big Numbers – Gameweek 1

Having heard a lot of rubbish being spouted by every man and his dog about Spurs’ move to Wembley, I thought I’d share my (relatively educated) knowledge about home advantage (HA) - and inevitably add to the uncertainty.

After a lot of research, last year I wrote a 5000 word paper on the causes of home advantage in football - for what it’s worth I genuinely think it’s worth at least a skim read if you are a football geek like me, so feel free if you wish: https://www.docdroid.net/ntGglha/what-causes-home-advantage.pdf

My conclusions as to what causes HA are illustrated in this model: https://gyazo.com/9bd740e8d1e51a2e3349eb5f9a19eeaf

“So, what is HA in football and how will Spurs be affected?”

 Football has a higher HA than almost all other sports

 When English football started, around 70% of all points were accrued at home (and 30% away), which has steadily dropped to around 60%/40% nowadays, with the most severe drop coming in the past 3 decades or so

 Research has shown home advantage to be worth around 0.6 goals per game, and that it is as good an indicator of the result as the abilities of the two teams in a sporting contest

 HA varies hugely between each country, but is present in all major leagues

 HA is much less in Women’s football, amateur football, derbies and FA Cup matches - bizarrely it is non-existent in FA Cup quarter finals

 Referees objectively show bias towards home teams, due to the crowd. This won’t change for Spurs this season. However, research suggests that a noisier atmosphere creates more officiating bias - personally I think WHL had the edge over Wembley in this regard but that is subjective.

 Home players perform objectively better at home than away (e.g. pass completion, tackle success etc)

 An increase in capacity such as the one Spurs will experience does *not* increase HA

 Familiarity both on and off the pitch is an important factor in causing HA - on-field familiarity will be lost by Spurs (but note many have played there multiple times already) but much (but not all) off-field familiarity will remain

 For slightly mysterious reasons involving instinctive territoriality, home players have about 50% higher testosterone levels than away players, which effectively acts as a very useful performance enhancing drug. I’m not sure if this will be affected by the move but if I had to guess I’d say it will.

 A study looked at 37 teams from several sports which changed stadiums but stayed in the same city, like Spurs. In the first season after moving, home advantage decreased for 26/37 teams, by an average of 24%…
Spurs scored 53 points at home and 33 away last year, a HA of 62%. If HA decreases by the 24% expected they could score 48 points at home and 33 away if their overall form is at the same level as last year - the equivalent of a draw and a loss in two games they won last year. This is a very basic example and you’d really need an average over several recent seasons to make a good prediction but it gives you some idea: 81 points in total, not exceptional but not a disaster, and still a HA of 59%.

 However, Spurs’ experience of playing games there already last year in the CL is a good sign, as is the number of England internationals they have, and could easily mean that the loss of HA is less than normal.

 Other subjective considerations: you could well argue that the switch and bigger pitch has given Spurs players a ready-made excuse and reduced confidence and motivation; you could also say that teams will see a trip to Wembley as a ‘cup final’ and therefore show more confidence and motivation. Both are conjecture though and personally I’m not convinced by either.

 TL;DR: Spurs’ home advantage will probably be slightly less than in recent seasons - but the overall effect on performance should be fairly insignificant, and they are more than capable of getting 80+ points. They will almost certainly still gain considerably more points at home than away - comments like “Spurs have 38 away matches this season” are nonsense.