Home Field Advantage

Podcast Transcript

In almost all sports, people will refer to what is known as having a home-field advantage.

Home-field advantage is a simple concept. It implies that teams playing in their home stadium, arena, or field have a slight advantage over the visiting team.

But is home-field advantage a real thing? And if it is, what are the reasons for it, and which teams and which leagues have the largest home-field advantages?

Learn more about home-field advantage and if it is, in fact, a real thing on this episode of Everything Everywhere Daily.

I might as well cut right to the chase. Home-field advantage is a real thing.

In fact, it is a pretty easy thing to verify. All you have to do is look at the winning percentage for home teams versus away teams.

However, to make sense of this, you can’t just look at a single team. A team might be really good or really bad. A bad team is going to lose at home and on the road, and likewise a good team will win on the road and at home.

To truly figure out if home-field advantage is real, you need to look across all teams in a given season or multiple seasons. For any sports league, the league-wide winning percentage will always be .500, even if the league has ties. The only way to avoid this would be if double wins or double losses were possible.

Home-field advantage has been observed at every level of competition in almost every sport. The only difference is the degree to which home teams have an advantage.

Let’s start with baseball simply because we have such a large data set. Since 1901, every team has played a season with either 154 or 162 games, save for strike seasons or seasons shorted by the pandemic.

If we go back to 1869, the start of professional baseball, there have been over 220,000 games played.

During that time, with that large data set, the home team won 55% of all games.

In the NFL, the home-field advantage usually is between 55 to 60% each season. Given the smaller number of games played each year, there is more variation in the winning percentage.

The NBA, which plays more games than the NFL but less than baseball, has a steady home winning percentage of about 60%.

In the National Hockey League, the home winning percentage is about 55%.

The American professional soccer league, Major League Soccer, or MLS, has a home-field winning percentage of 69% if you assume ties are half wins and half losses.

This isn’t just a phenomenon of North American professional sports.

In Division 1 men’s college basketball, the home winning percentage varies from 67 to 69% in most years.

In international cricket, the home-winning percentage is 60.1%.

In Rugby Union, its around 58%. In Japanese professional baseball, it is one of the lowest at just 53%.

In the 2022-2023 season in the English Premier League, using the same metric as with the MLS, the home wining percentage was 60%.

So, the effect is real, and every student of sport knows this to be true.

The big question is, why?

As easy as it is to verify the existence of home field advantages, coming up with a root cause is much more difficult. Without any knowledge or data, you could probably come up with some hypotheses about why this is the case.

One of the popular reasons that is often given is that visiting teams are at a disadvantage because they have to travel. Traveling can be exhausting. They are in a place that they may not be familiar with, they might be tired from traveling, and possibly even suffering jet lag.

For international competitions, there might be the issue of being in a different culture with different foods.

Home teams get to sleep in their own bed and keep to their normal routines.

One of the problems with this theory is that home-field advantage holds even for teams that play in the same city or don’t have to travel very far.

There have been cases where there are two teams from the same city who play each other, and despite removing travel from the equation, home-field advantage still holds.

I should note that while traveling doesn’t appear to be “the” reason for home-field advantage; it very well might be a contributing factor, especially when teams travel long distances.

The second obvious explanation would be th the actual playing fields are different.

This is peculiar to each sport. In many sports, there is little to no variation in the size of the court or field. Soccer pitches can have some variation in field size, but other parts of the field are constant.

NFL fields and NBA courts have the exact same dimensions. NHL and International hockey rink sizes vary slightly but not significantly.

So, it is hard to use the field itself as the explanation for the large imbalances in winning percentages.

However, there are sports where the field can make a big difference.

Baseball fields famously have identical infields but can have vastly different outfields.

One of the craziest baseball stadiums ever built was the Polo Grounds in New York City. The Polo Grounds was the home in the early 20th century to both the New York Giants and the New York Yankees.

The Polo Grounds had an outfield wall in dead center field of 483 feet. That is monsterous by today’s standards. Most stadiums have their deepest point in centerfield of 400 feet or less. The outfield was shaped like a rectangle with the corners at a still impressive 450 feet.

However, the right field corner was only 258 feet. Depending on where you hit the ball, it was either really easy or almost impossible to get a home run.

Fenway Park in Boston has its Green Monster which is a close wall at 310 feet, but its 37 feet high.

Wrigley Field in Chicago has an outfield wall made of solid brick covered in ivy.

Cricket, likewise, has ovals that can differ in size. A four or a six in one stadium might not be in another.

In baseball, football, and soccer, there are also differences in surfaces. Some fields have natural grass, and some have artificial turf. Artificial turf is considered to be faster than natural grass.

Weather and climate are also other factors that can come into play. Cold weather teams that play outdoors are often thought to have an advantage over warm weather who visit and who are not used to the cold.

The NFC North is considered to have the teams who play in the coldest climate in the NFL, but with the Chicago Bears announcement of a new stadium, three of the fourt teams will now play indoors, leaving only the Green Bay Packers to play outside.

They’ve used their unique playing conditions to garner a home winning percentage over 70% in the last 10 years. From 2013 to 2022, the Packers had the largest difference in winning percentage between home and away games.

A very special case is that of Denver.

Denver is known as the “Mile High City,” because it is located at an altitude of 5,280 feet above sea level.

Nothing is even close to Denver in terms of altitude in terms of other American cities with major sports teams.

The altitude can affect visiting athletes’ performance in several ways, particularly through reduced oxygen levels, which can lead to quicker fatigue and slower recovery times.

Also, the thin air reduces air resistance, allowing baseballs to travel farther than at lower altitudes. This phenomenon significantly increases the number of home runs hit at Coors Field. To counteract this, the Rockies have used a humidor since 2002 to store baseballs in a moisture-controlled environment, somewhat mitigating—but not eliminating—the altitude’s effect on the game. The Rockies are the only team allowed to do this.

Not surprisingly, Denver was the location of both the longest punt and field goal in NFL history.

Cities such as Mexico City and Quito have altitudes much higher than Denver which make playing there difficult for visiting teams.

Then there is also the noise factor. Stadiums tend to focus noise and they can get very loud. In the NFL this can make things very difficult on opposing teams who have to communicate on the field.

Lumen Field, where the Seattle Seahawks play is considered to be the loudest stadium in the world. It is listed in the Guiness Book of World Records as the loudest with a volume of 137.6 decibels which was measured in 2014.

Despite these massive differences in altitude, climate, and fields, many people who have studied the matter do not think that any of these are major reasons for the discrepancy in home-winning percentages.

The one factor that has the data to support it affecting winning percentages is crowds….and it isn’t for the reason you might think.

Ask most athletes, and they’ll tell you that it means a lot to have their fans cheering for them, which is probably a contributing factor. In some stadiums, like in Seattle, the sheer volume can be a factor.

However, one factor which has been measured and found over and over again in different sports are the calls made by referees and umpires.

Even though its not intentional, officials have a bias in favor of the home team.

When a batter has a full count in baseball, a pitcher from the home team is more likely to have a pitch called a strike.

Overall in the NHL, the home team gets 20% fewer penalties called against them, which results in about a quarter of a goal per game.

In the NBA, traveling is less likely to be called against the home team and fouls are more likely to be called against the visiting team. This resulted in 0.8 more free throws, or 0.6 points per game for the home team.

How do we know that this bias is due to fans and not something else?

Mainly because we have been able to test it.

In European soccer, referees called more fouls against visiting teams, however, that dropped when teams played in a stadium with a track around the outside, which put more distance between the officials and the fans.

The NFL offered a grand experiment in 2020 during the pandemic when games were played without fans. For the only time in NFL history, the visiting teams won more games than they lost. Granted, it was only one more game, but the only season with no crowds did correspond to the only season where the home team didn’t have an advantage.

There is one other element of home field advantage that I should bring up because as of the time I’m recording this, it is something that is in the news. The Olympics.

Every Olympics there is a curious thing that happens. The host country almost always wins far more medals than they did the previous Olympics.

In the last 75 years, there have been only two olympics where the host country didn’t win more medals than the previous olympics; Finland in 1952 and the United States in 1996. In both cases, it was only a very slight decrease, whereas the increase in the medal count is usually quite large.

The usually explanation given for this is similar to why teams tend to win at home. Its due to the crowds and the lack of travel.

However, that isn’t the real reason.

The real reason why host countries do so well is because they are allowed to bring many more athletes than they otherwise would. They simply have more people competing which gives them more chances to win medals.

If you normalize medals on a per athlete basis, then the host country advantage totally disappears. It stays the same or actually decreases.

One thing I’ll close with is that across the board, home field advantage seems to be decreasing over time. Its still there, but it appears to be going down. Again, no one is sure why or if the trend will continue, or if it will become more pronounced in certain leagues.

In 2019, the World Series went to a full seven games, and for the first time in history, the visiting team won every game.

Home field advantage is a real thing and it is important enough that teams often fight for it to have an advantage in the playoffs. In sports that determine champions in a single game, it will often be played in a neutral site for this very reason.

So, if you ever get to choose between playing at home or on the road, your choice is easy. Play at home.