"A New York Treasure" --Village Voice

Color By Numbers: There’s No Place Like Home

One of the most controversial things about the World Series is how home field is determined. Unlike other sports, which either use a neutral field or assign home field to the team with the better regular season record, baseball has decided to link the extra home game in the Fall Classic to the outcome of the Midseason Classic. To some, this connection borders on the absurd, but does home field in the World Series really matter?

Several studies have been done on this topic, and most, like this one, have concluded that there really is no advantage to home field in the baseball postseason. However, analyses that focus on series outcomes, instead of individual games, can be misleading. After all, if the home team wins four of the first games in a best of seven series, the team without the advantage would emerge victorious.

Root for the Home Team? Postseason, Regular Season Records at Home

* Since 1919
Source: Baseball-reference.com

Not including last night’s opener in St. Louis, the home team has won 339 of 614 World Series games, or just over 55%. In essence, during the Fall Classic, there is a 17-win difference between home and road teams (based on a 162-game season), so where each game is played seems to have a significant impact. Although some might question the sample size, the 55% win rate for the home team is not only in line with the percentage in the entire post season, but also closely mirrors the outcomes of every regular season game played since 1919.

The team with home field advantage has won the World Series 58 of 102 times (excluding four World Series that featured eight games), a percentage that is in line with the 55% per game win rate cited above. However, because the “road team” in a seven game series is the first to host three games (thanks to the 2-3-2 format), conventional wisdom has suggested that only in a deciding game seven does the ballpark really matter. And yet, a closer look into the actual results tells a different story.

Home Team Record by World Series Game

Source: Baseball-reference.com

There have been 35 winner-take-all game 7s in World Series play, and the road team has won 18 of them. However, actually getting to the seventh game hasn’t been as easy. In games 1, 2, and 6, the home team not only enjoys a significant advantage, but it is also much greater than the one exhibited in games 3, 4, and 5. Apparently, in order for a team without home field advantage to win the Fall Classic, survival is the key (over 45% of World Series won by teams without home field came down to a winner-take-all game). Then again, the last eight game 7s have all been won by the home team (the 1979 Pirates are the last team to win a double elimination game as a visitor),  so even this one refuge for the road team has been taken away.

Because baseball has used a random method of assigning home field for most of its history, it’s hard to explain why there hasn’t been much of an advantage in the middle three games. Perhaps it’s because those games are more likely to feature second tier starters, which mitigates the advantage? Or, maybe the momentum (which for many sabermetricians is a dreaded concept) of early success carries over to the rest of the series? Regardless of the reason, it seems clear that home field advantage not only impacts the number of games a team has in its own ballpark, but how well they perform in front of the hometown crowd.

Home Team Performance in the World Series, by Decade

Note: Eight game series excluded from calculations.
Source: Baseball-reference.com

A breakdown of World Series results by decade reveals significant fluctuations in the impact of home field advantage, which shouldn’t be surprising when you consider the random manner in which it was determined for almost 100 years. Nonetheless, it’s interesting to note that in the 1940s, when the road team won 53% of all Fall Classic Series games, the team with home field advantage won 90% of the World Series. Then, in the 1950s, the opposite happened. That decade, home teams won 61% of all games, but 70% of the World Series were won by the team starting off on the road.

Although there seem to be so many conflicts and counterintuitive aspects of the data, we can definitively say that home field advantage in the World Series matters. After all, 23 of the last 30 Fall Classics have been won by the team that hosted game one. Of course, that brings us back to the question of whether such a meaningful reward should be granted based on the outcome of the All Star Game. I would argue yes, but it’s easy to see why others might disagree. Regardless of one’s position, however, what seems clear is that fans, players, and teams should probably starting take the midseason classic a little more seriously because, nowadays, it really does count.

Yogi, by Yogi


1 Alex Belth   ~  Oct 20, 2011 11:17 am

Nice piece, man. I know the Lords of the Realm want the All Star Game to mean something so they can draw ratings but it seems to me that the fairest way to determine Home Field is that it should go to WS team with the best regular season record.

2 Jon DeRosa   ~  Oct 20, 2011 11:45 am

linking this back to the study that showed that almost all of the home field advantage is in biased umpiring/officiating, i wonder if the heightened atmosphere of the world series, the extra amped up crowds, influences the umps even more than usual, accounting for the uptick in the WS home field advantage over the regular season.

3 ms october   ~  Oct 20, 2011 12:09 pm

interesting piece and analysis william.

i have never liked the idea that the asg is tied to homefield and have become even more opposed to it over time.
a team with a slightly better than middling record like the cards should not have homefield advantage.

[2] that seems to make a lot of sense.

4 William J.   ~  Oct 20, 2011 12:13 pm

[1] In the link, I address that point in more detail, but I don't think NL and AL schedules are congruous enough to make the best record approach more meaningful than random. Also worth noting that the ASG method has given home field to better record in 7 of 9 years.

[2] Perhaps, but the uptick really isn't that big. Having larger crowds could explain the difference (although that could also incorporate umpire bias). It would be nice to do a study comparing HF based on attendance figures, but don't know of a database that has such information.

5 William J.   ~  Oct 20, 2011 12:16 pm

[3] I am actually a big supporter of the ASG link because I do think it spices the game up. I also think the ASG outcome can indirectly funnel HF to the better team, and is at least much better than the random approach.

6 ms october   ~  Oct 20, 2011 1:01 pm

[5] perhaps when the al was winning all those asgs :}
i am definitely not a fan of the random approach.
but there is really no good reason why home field cannot go to the actual team with the best record.
the nba has more teams in the playoffs and thus more potential sights for where the finals ends up being so the logistics argument is crap to me.

the cards got home field this year because their current biggest rival's chubby 1b hit a home run in the asg - i don't see how the cards had anything to do with that :}

7 ms october   ~  Oct 20, 2011 1:01 pm

[6] ugh - sights = sites

8 William J.   ~  Oct 20, 2011 1:32 pm

[6] Because schedules are so different, I don't see the point in assigning home field based on an apples-to-oranges comparison. For example, winning 94 games in the NL Central is not better than 91 games in the AL East, so why grant home field in that manner.

I think there are two legit approaches: (1) develop a saber-type formula to normalize differences and come out with a rating; or (2) have some fun with it and attach to the ASG, which does have way of representing which league is better.

9 RIYank   ~  Oct 20, 2011 1:56 pm

My bet is that the loss of the home field advantage in the middle games of the Series is: pure chance.

I do think the total number of WS games played is large enough to support the conclusion that the home field advantage overall is a real one. Here's one way to quantify this judgment.

The null hypothesis is that there is no home field advantage at all, that knowing which team is the home team in some future game will give you no information about who will win. Our alternative is that there is a home field advantage (it does not include that there is a disadvantage -- it's obviously reasonable to use a 'single-winged' test). The data in William's table support rejection of the null hypothesis with significance at the .005 level. That means if you just modeled the games by a coin flip, the chance of getting a result as skewed toward the home teams as the historical results are is tiny -- a half of a percent. It's extremely unlikely that the results are just due to noise.

(The confidence interval here is .513 to .591. That is to say, we can be 95% confident that the real advantage to the home team is somewhere in there -- the best guess is that it's the 55.2% that we actually saw, but it wouldn't be hugely surprising if the true advantage were as small as a little over a percent or as large as 9 percent.)

But the sample size for the middle games doesn't support any interesting conclusions about those games. If we just take the simple hypothesis that in every single game being the home team gives you a 55% chance of winning, we should not be at all surprised to see that in a historical data set there are some spurious patterns, patterns like the loss of the advantage in middle games. My bet is that's what's going on in the data.

10 William J.   ~  Oct 20, 2011 4:00 pm

[9] What he said!

Seriously, I'd be inclined to accept the middle games being the product of chance, if 1,2, and 6 didn't all have a much higher winning percentage than 3,4, and 5.

11 RIYank   ~  Oct 20, 2011 4:52 pm

[10] Yeah, well. The test is a little more complicated and I don't feel like doing it, but to me that looks like a bell curve around .55, with three of the four lowish ones all clumped together, just coincidence.
If there were some antecedent reason to expect the middle games to be different, then I'd be more inclined to think it was 'real'.

12 RIYank   ~  Oct 20, 2011 4:54 pm

Oh, and by the same token, the fact that the overall winning percentage of home teams in the Series is so close to overall winning percentage of home teams in the regular season makes the Series trend much stronger even than the chi square test indicates.

feed Share on Facebook Share on Twitter Share via email
"This ain't football. We do this every day."
--Earl Weaver