Since 1995, home teams have won 53.936 percent of baseball games played in the regular season. Considering that a large portion of home field advantage is, by conventional wisdom, attributed to the effects of home-crowd fans (either on the players, or, more likely, ontheumpires), we might reasonably expect the home team to get an even bigger boost during October, when the crowds are bigger, perhaps more partisan, and generally more bananas.
The Rays are 12-1 at home this season. Where does their home-field advantage come from?
While looking toward the future with our comprehensive slate of current content, we'd also like to recognize our rich past by drawing upon our extensive (and mostly free) online archive of work dating back to 1997. In an effort to highlight the best of what's gone before, we'll be bringing you a weekly blast from BP's past, introducing or re-introducing you to some of the most informative and entertaining authors who have passed through our virtual halls. If you have fond recollections of a BP piece that you'd like to nominate for re-exposure to a wider audience, send us your suggestion.
What is it about Tropicana Field that makes the Rays so successful at home? Nate looked at the origins of home-field advantage and made some interesting discoveries about domes in the article reproduced below, which originally ran as a "Lies, Damned Lies" column on June 29, 2008
If you want to estimate run-scoring accurately, what are all the factors you need to take into account?
The forces that influence run-scoring
As a reader of this site, you would be suspicious of any article that compared a starter’s ERA and a reliever’s ERA without making any adjustment for role: it has been shown several times (including by yours truly) that the luxury of pitching in short bursts and not having to face the same batters multiple times in a single outing significantly deflates relievers’ ERAs.
Similarly, we can’t model run-scoring on a team level without accounting for all the factors at play at any particular time. Many elements combine to shape the distribution of runs scored. Some of them are quite obvious, while others remain hidden until they’re exposed by the most brilliant analysts. In the following paragraphs, I’ll try to evaluate as many of those components as possible in an attempt to isolate their individual effects on offensive outcomes.
The rest of this article is restricted to Baseball Prospectus Subscribers.
Not a subscriber?
Click here for more information on Baseball Prospectus subscriptions or use the buttons to the right to subscribe and get access to the best baseball content on the web.
Home teams are winning their games at an increased rate over the last few years, but is it a trend that's likely to continue?
A few weeks ago, I wrote about how home teams had improved their performance in the last three years. After winning about 54 percent of games consistently for the last 60 years, home teams have won 55.5 percent of games in the last three seasons. Although it is just a 1.5 percent increase, there has not been a three-year period with home team winning percentage this high in 60 years, so there may be a noticeable reason for the shift.
Why are home teams winning more now than in previous eras?
When I wrote my five-partseriesonhome-fieldadvantage in 2009, I noticed that it had been steady at about 54 percent for over half a century. It was 53.9 percent in the 1950s, 54.0 percent in the ‘60s, 53.8 percent in the ‘70s, 54.1 percent in the ’80s, 53.5 percent in the ‘90s, and 54.2 percent in the 2000s. However, in the last three years, we have seen home teams win 55.5 percent of the 7,288 games played, a very statistically significant difference. Does this suggest that a large change has actually taken place, or is it just a coincidence? If a change has taken place, what is causing it?
Should the Yankees and Rays pull out all the stops in order to win the division and potentially gain home-field advantage in the ALDS and ALCS?
Over the next four nights, the battle for the American League East will rage in the Bronx, as the Yankees host the Rays for the teams’ final head-to-head confrontations of the regular season. Scant daylight separates the two clubs in the standings, as the Rays enter the (Evil) Empire State trailing the division-leading Bombers by just a half-game, and tied in the loss column. That may sound like a pressure-packed scenario, but at this point in the season, it’s safe to say that each team has become accustomed to hearing the other’s footsteps:
How much of an edge do the Phillies have by playing three "home" games against the Blue Jays at Citizens Bank Park?
On September 26, 2007, the Cleveland Indians won a “home game” against the Seattle Mariners at the Mariners’ home ballpark, Safeco Field. The original game along with a three-game series had been snowed out in April that season. Two of the games were made up during the season in Cleveland on mutual off days. However, without a third mutual day off, the teams simply made up the game as part of a regularly scheduled series in Seattle. While other games had been up in the opponent's home ballpark, Major League Baseball decreed that the Indians would be the home team in this game. Thus, for the first time since 1913, a team batted first in its own park.
Wrapping up the review of home-field advantages to see if there's anything extra we might be missing.
This is the fifth and final article in this series on home-field advantage. The first four parts of this series have revealed many things. In the first article of this series, we studied what home teams are able to do more frequently than road teams; we learned that they pretty much do everything better, hitting more home runs, reaching base more frequently on balls in play, walking more often, striking out less often, stealing more bases, making fewer errors, and recording more complete-game shutouts. In the second article, we learned that nearly all home teams enjoy relatively similar home-field advantages over time, with the exception of the Rockies, and that the vast majority of year-to-year fluctuations in teams' home-field advantages are random fluctuation. The third time around demonstrated the important role of distance and familiarity in determining home-field advantage, and noted that home-field advantage was much larger in interdivision games than intradivision games, and was especially large in interleague games. We discovered something quirky in the fourth article of this series, that not only was the first game of the series not any more likely to exhibit home-field advantage, but the penultimate game was. More peculiarly, it was statistically significant, indicating that it is not all that likely to be merely noise. I received many e-mails and comments suggesting reasons that this peculiar effect may be real, or expressing skepticism that it is more than merely noise. This indicates that there is probably more to be learned about home-field advantage, and more that is not immediately obvious.
Is there a surprise to be found in terms of the in-series pattern of home-field advantage?
In the first three articles of this series, we have studied what home-field advantage affects, who it affects most, and where it shows up most. We have found that home-field advantage affects nearly every aspect of a team's performance, including pitching, defense, baserunning, and offense. We found that the Rockies are the only team that has statistically significant home-field advantage, and that most other teams are bound to win about eight percent more games at home than on the road in the long-run. We also found that home-field advantage was larger in interleague games than intraleague games, larger in interdivision games than in intradivision games, and even within divisions, it was larger the further apart the teams played. This suggested that travel might be playing a significant effect in home-field advantage. Further evidence of this came from the fact that interleague games within teams in equivalent divisions (e.g. East vs. East) had smaller home-field advantages than interleague games where longer travel distances were involved.
Drilling down even more deeply into the subject to find out where, why, and how.
In trying to understand home-field advantage, we have asked what home-field advantage actually makes a team do better, and we have asked who has the biggest home-field advantage. The first article of this series answered the question of what home-field advantage actually makes you do better-everything, as home teams do better on walks, strikeouts, balls in play, and errors. They are better at pitching, hitting, baserunning, and defense, and all aspects of their games seem to improve. The second article of this series showed that most teams have pretty much the same size home-field advantage, with the exception of the Rockies. Even though natural luck can make a team look like they are particularly good or bad at home, the 29 non-Rockies teams are pretty much right around eight percent home-field advantage, plus or minus a little statistical noise.