Keeping Score: An Edge to Friendly Confines
- May 27, 2010
In major league baseball from 2000 to 2009, the home team won 54 percent of the time. Many cite the home team’s last at-bat as the reason. At the end of games, the thinking goes, the home team can tailor its strategy to match the situation. If the team is down by three runs, it can play for the big inning. If it needs one run, it can use small-ball strategies like bunting and base stealing to get that run.
If only it were true. Recent research has found that having the last at-bat is not a statistically significant advantage. Three professors — Theodore Turocy, the data manager for the Society for American Baseball Research and an economist at East Anglia University in Norwich, England; and Stephen Shmanske and Franklin Lowenthal, professors at California State University, East Bay — have used simulations and examined data to debunk this myth.
SRS combines the average margin of victory and strength of schedule to determine number of runs per game better than an average team each team is.
Instead, the home-field advantage in baseball has to do with a more mundane reason: familiarity with the ballpark. This comes through in extra-base hits. Because baseball fields do not have a consistent outfield shape, size or turf, outfielders have adjustments to make between parks. Among balls hit into the outfield, home teams have more hits, especially triples and inside-the-park home runs.
Batting Runs measures the number of team runs created by the batter (through hits, walks, hit-by-pitch) relative to that of a league-average player. This is also adjusted to the park played in.
Total Zone is the number of runs saved by the fielder when compared to an average fielder. It considers balls fielder, double-play turns for infielders and arms for outfielders.
We can also look at the home-field advantage of newly opened ballparks. There have been 25 ballparks with a full season of play that have opened since 1980. Surprisingly, the home-field advantage in their first year is only 52.3 percent, but that number steadily rises through the fourth season, to 55.1 percent. Only in the fifth year, as opponents’ comfort rises in the ballpark, does it begin to drop, to 53.3 percent. It appears that the home team has to learn the stadium itself and then has a significant advantage until the rest of the league catches up in four to five years.
Both the Mets and the Yankees got off to fast starts in their new stadiums last season, winning about 14 percent more games at home. And this season, though it is young, the Mets have soared at Citi Field, with an 18-9 home record compared with 6-14 on the road going into Thursday night’s game against the Philadelphia Phillies.
Another factor in home-field advantage is distance traveled. Last fall, Matt Swartz of Baseball Prospectus published a five-part study on home-field advantage corroborating the effect of familiarity and also finding that the longer the distance traveled, the larger the home-field advantage.
On the question of distance traveled, Swartz did not find a difference between the road team’s play in the first and last games in the series. In fact, road teams played worse in the middle games of the series. Perhaps teams suffer from jet lag early in the series and homesickness at the end of the series and both in the middle of the series. No one is quite sure of the reason, but the effect appears real.
There may be one group of ballplayers, however, who benefit from going on the road — those with newborns. Melvin Mora and his wife, Gisel, had quintuplets on July 28, 2001, while Mora was a starting outfielder for the Orioles. From that date until the end of the 2002 season, Mora hit .254 on the road and .205 at home.