Lesson 06 · 3 min · 5 things to do
What home advantage is made of
Separate the parts of an effect everyone accepts and few examine.
Home teams win more often across almost every league and sport. What is the effect made of?
- Yes.No single cause explains it. Each part is modest, and together they are worth a substantial share of a point per match in most leagues.
- Not quite.The most popular explanation, and the weakest in the evidence. Player output measures barely change; officials' decisions do.
- Not quite.A real and small contributor, larger in sports with genuinely different venues.
Home advantage is not one thing. It is a stack of small effects, and they can be measured separately because they do not always appear together.
Matches were played without crowds for a period in several leagues. Slide to see what happened.
Full crowdEmpty stadiumWhat changed mostHome team1.6 pts/matchAway team1.15 pts/matchFull crowdThe usual home advantage. Home teams take clearly more points per match.
Home team1.4 pts/matchAway team1.3 pts/matchEmpty stadiumThe gap narrows sharply — and does not disappear.
Cards given to away teams−25% change with no crowdDistance run by home players−1% change with no crowdWhat changed mostFouls and cards evened out between the teams. Running and shooting barely moved.
Removing the crowd changed the officials more than the players. What does that suggest?
- Yes.Referees are not cheating — they are people making split-second judgements while thousands of them shout in one direction. It is one of the clearest natural experiments sport has ever produced.
- Not quite.They report caring a great deal. What the measurements show is that their output changes very little.
- Not quite.Away from the crowd, the effect largely disappears — which points at the environment, not the official.
Move the control to see what changes.
Which parts of home advantage survive an empty stadium?
The away team's travel and sleep disruption.
Familiarity with the pitch and surroundings.
The crowd's effect on marginal decisions.
No need to travel the day before.
The noise when the home team attacks.
Yes.The surviving parts are logistical. That is why home advantage is largest in leagues with long journeys and smallest where two clubs share a city.Home teams average 1.6 points a match and away teams 1.15. Over 19 home matches, how many points is the advantage worth?
pointsYes.0.45 × 19. Eight points is often the difference between qualifying for something and not — produced by an effect nobody had to earn.Why is it worth knowing what an accepted effect is made of?
- Yes.Travel can be scheduled around and pitch familiarity cannot be shared. Knowing which part is which turns a piece of folklore into something a club, or a league, can act on.
- Not quite.It is large, consistent and measured across a century of fixtures.
- Not quite.It has been shrinking slowly for decades, and it is still clearly present.
Lesson complete
Home advantage is a stack of small effects, and the crowd's part runs through the referee.
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