Last Sunday, I had an article in the Boston Globe Ideas section on the underlying causes of home field advantage.
The Celtics are an extreme example of a sporting phenomenon known as home-field advantage: teams playing on their home field, or court, are significantly more likely to win. The advantage plays a role in every major sport. Home teams in the NBA have a 62 percent chance of winning, while those in Major League Baseball and the National Hockey League have a 53 percent chance of winning. (Football teams are somewhere in between, with annual ranges typically between 54 and 64 percent.) Although the effect has declined over time - in 1950, home teams in the NBA won 75 percent of all games - playing at home remains one of the most significant advantages in professional sports.
"Athletes spend so much time and energy looking for any kind of edge," says Albert Carron, a professor of kinesiology at the University of Western Ontario. "But nobody's found another edge this powerful."
Personally, I was most surprised by the fact that playing on a familiar playing field seems to confer a large advantage, even in sports (like basketball) where the playing field is supposedly uniform.
For example, a 1995 study showed that British soccer teams playing on "nontraditional pitches" - fields that are either longer or shorter than normal, or consist of artificial turf - enjoyed a larger than normal home-field advantage. Another study compared the home winning percentages of NBA, NHL, and MLB teams before and after they moved to a new stadium. For 26 of the 37 teams, there was a decrease in the home advantage following a move. Because the new venue was unfamiliar - the players had yet to learn the secrets of the parquet floor - they were less likely to win.
For some interesting things about real home field advantage in baseball in the old days read "Crazy 08" which is about the 1908 baseball season. (When the Cubs were so good they won every key game...) Cobb's swamp of a watered infield was no joke. Groundskeepers were paid almost as much as players. The infield lines would be sloped differently depending on pitchers, who had lefties, etc. This went on til the 1990's at least with even Ricky Henderson complaining (or was it really complimenting?) about the White Sox groundskeeper who could really slow down the basepaths for running. That guy actually took it as a compliment and said that they hadn't touched on his real bag of tricks.
Re: basketball - how shiny is the floor and lights - where are the reflective ads? How slippery is the floor? How does the other team respond to these - does their point guard like a slightly slippery floor to slide by? Or does he like a grip? There are a lot of variables and nobody I think will really talk about the real ones.
I think the importance of this effect in series' outcomes is overrated. If two equally good teams face each other (home team has a constant probability of winning of 62%) the one with home court advantage will have a 54% chance of winning the series overall. So whatever advantage home court provides is very much diluted by playing best-of-7 series.
FYI: in SI this article, the author suggests that the layout and location of the visiting team's locker room gives an edge to the San Antonio Spurs. Go Spurs!
For some interesting things about real home field advantage in baseball in the old days read "Crazy 08" which is about the 1908 baseball season. (When the Cubs were so good they won every key game...) Cobb's swamp of a watered infield was no joke. Groundskeepers were paid almost as much as players. The infield lines would be sloped differently depending on pitchers, who had lefties, etc. This went on til the