Is home advantage real in sport?

Yes. It is one of the most consistently measured effects in sport, appearing across essentially every team sport, every league and every level studied. What is less settled is why.

The size varies by sport. In football, home teams have historically won somewhere around 45–50% of matches against roughly 25–30% for away teams. Basketball shows a substantial effect, baseball a smaller one.

Several explanations have been proposed, and the evidence for them differs considerably.

Crowd influence on officials has the strongest support. Studies have found referees award more stoppage time when the home side is behind, and give fewer cards against home teams. This appears to be an unconscious response to crowd noise rather than deliberate bias — a well-known study found officials watching recorded matches gave different decisions depending on whether crowd noise was audible.

Travel and fatigue matter, particularly where distances are large or time zones are crossed. Effects are measurable in leagues spanning a continent and small in compact ones.

Familiarity with the pitch, surface, lighting and conditions has some support, stronger in sports where venues genuinely differ, such as baseball parks.

Crowd support raising player performance is the most intuitive explanation and has the weakest evidence.

The matches played behind closed doors during 2020 and 2021 provided an unusual natural experiment. Home advantage shrank substantially but did not disappear, and the referee-decision gap narrowed markedly — which supports the officiating explanation as a major component while indicating it is not the whole story.

Home advantage has also declined gradually over decades, plausibly as travel has become easier.