Alex has asked me to do something that scares me a little bit. So I’m going to try it. I am troubled by the size of the home field advantage in baseball — it seems way too small. So I’m going to do a study, but Alex wants me to do it in public at Braves Journal, so I’ll give it a try. Let this post be an introduction, and we’ll see how it goes.
Baseball is unique as a sport in a number of ways. First, more than any other game, the rules as written favor the home team. (I am limiting this thought experiment to the four big US sports, plus soccer.) Hockey is a distant second, and football, basketball and soccer are essentially home/road neutral. Hockey comes in second because it allows the last change to the home team in a faceoff situation. But the baseball rule which allows the home team the last at-bat should be a sizeable advantage for any number of strategic reasons, and no other sport has anything like it.
Baseball is played on the least uniform set of fields, by far, allowing teams to differentially accomodate themselves to their home parks where they play half their games. This should both increase their fitness at home and decrease it doubly on the road. (Hockey gives a penalty box placement advantage to the home team, and of course some rinks are smaller than others, though most are the same size. Football has surface, weather and wind differences. Basketball has, I suppose, different sightlines and the famed Boston Garden dead spots, but that’s about all I could come up with. Qualitatively, the Pesky Pole, Citizens Bank Park’s fences and Coors Field should easily surpass all of these.)
Baseball also has by far the longest season and a unique pattern of series of games, rather than one-off games randomly sequenced through the season. Thus, when a baseball team arrives in a town, they play two, three or four games; almost never one. No other sport does this. I think this effect should lower the home-field advantage somewhat, although the mechanism is to me somewhat unclear.
There have been a number of studies of home-field advantage in a number of sports, and a fairly recently published metastudy, by Jeremy Jamieson of Northeastern University, across sports. The result is that baseball has by far the smallest homefield advantage. This is attributed (at least in this article and somewhat tentatively) to the long season, though I have no idea why a longer season should lower the home field advantage.
Jamieson makes the argument that in long seasons, individual games are less important, so whatever effects there are of fan rooting or umpire’s psychological desires to please rabid home fans will be reduced by a less boisterous crowd. In addition, he notes that playing three games in a row somewhere might lower the home field advantage somewhat by some sort of acclimatization or reduced travel per game effect.
I don’t buy it, but of course I’d like to see what the data say. And they certainly don’t account for the fact that sport that by its rules ought to have the highest home field advantage has the weakest. Somehow, the long-season effect must be much bigger than the rules and parks effects which go the other way. Does that make sense to you?
So what I’ve done thus far is download the linescore of every baseball game in history. I’ve made a few quick tabulations that I’ll present in the next installment (if there is one!), but I’d like people to look at the Jamieson study and/or give me their thoughts in the absence of data. As I said above, this is, to my mind, a different way to do research, and a somewhat scary one, but we’ll see how it goes. I want to understand the home field advantage in baseball (I really don’t care about it in the other sports very much.) So… what do you guys think?