How much is home advantage worth? League by league, and why it is shrinking

What home advantage is worth, league by league

The cleanest way to measure it is to ask how often a team beats an opponent of exactly equal strength when it plays at home. A study that estimated team strength from a decade of betting prices in the four big North American leagues found (Lopez, Matthews & Baumer):

• MLB: 54.0% — the smallest edge;
• NHL: 55.5%;
• NFL: 58.9%;
• NBA: 62.0% — the league with the largest home advantage of the four.

College football is usually measured in points: a recent survey of the research puts it at about 3 to 5 points per game in NCAA play, and “arguably dwindling” (survey of home advantage in American football). Home advantage also differs from team to team: Denver's home court is the strongest in the NBA (see What moves a game before it starts).

It is smaller than it used to be

In almost every league the home edge has been shrinking for years, and the market has followed.

• NFL: the league's own analysts estimated home-field advantage at 3.30 points in 2006 and 1.30 points in 2020 (NFL Football Operations). Over ten-season windows it fell from about 2.9 to 2.2 points between 2000 and 2019 (nfelo), and a sportsbook director now prices it closer to 1.5 points for most teams (FOX Sports).
• NBA: home teams won about 60% of games in the early 2010s and around 54% in most recent seasons (Yahoo Sports).
• MLB: the most stable of all — home teams have won about 54% of games across most eras since 1901 (MLB.com) — yet road teams won 47.9% in 2023, so home teams won only 52.1% (VSiN).

These are season totals, and a single season is noisy: in a year when strong teams happen to play more road games, the home figure drops without anything having changed. Read them as a trend, not as exact values.

What the empty stadiums of 2020 showed

The pandemic created an experiment nobody would have designed: games with no crowds. In 2020 NFL home teams finished 127-128-1, the first losing record for home teams in the league's history (theScore). A statistical study of all four leagues found that home advantage fell in the NBA's and NHL's strictly closed “bubble” playoffs, while MLB and NFL, with looser restrictions, showed little or no change (PMC).

The lesson is not simply “fans are the edge”. The NFL's home advantage was already at a low in 2019, before the pandemic (The Ringer), and a study of NBA free throws — the purest test of crowd pressure, since nobody defends them — found no difference between shooting at home and on the road (Pelechrinis, PBS NewsHour).

Why it is shrinking

Nobody has a definitive answer, and researchers still disagree about which causes matter most. The usual explanations are: easier travel (charter flights, better schedules, better recovery), more uniform venues, more replay review and more consistent officiating, and more parity between teams. Familiarity with the home park still matters in some places — altitude in Denver, a quirky ballpark — but much of what used to be a general edge for everybody has faded.

What it means for a prediction

Home advantage is already in the price. When a sportsbook or a prediction market makes the home team a 58% favourite, that 58% includes playing at home. Adding “and they are at home” on top of it counts the same thing twice — one of the most common mistakes when reading a game.

At iPick, each league's model does not use a fixed, hand-picked home bonus: the size of the edge is chosen from data, on past seasons, and it is set to zero for games on a neutral site. Because the edge drifts over the years, it is measured again whenever a model is retrained. And as explained in How iPick makes a pick, when an outside estimate exists, the pick follows the market, which already prices the venue.

In short

• Between equal teams, home is worth about 54% in MLB, 55.5% in the NHL, 58.9% in the NFL and 62% in the NBA.
• The edge has shrunk in most leagues, most clearly in the NFL and the NBA.
• It is already in the odds and in any good probability: do not add it twice.
• One season, or one stadium, says little; look at many games.