Thursday, June 19, 2008

Do teams play worse after a time zone change?

According to a resent research presentation by a Baltimore sleep scientist, baseball teams that have recently travelled across time zones play worse than otherwise.

It's called "Measuring Circadian Advantage in Major League Baseball: A 10-Year Retrospective Study," by W. Christopher Winter, M.D. It was funded by MLB.

The study was presented at a conference on June 10, but I can't find it online. (That drives me nuts -- the study is quoted by a whole bunch of press releases, the author is quoted directly, but the actual paper isn't publicly available? What's with that?)

The Scientific American writeup quotes the results this way: if a team travels three time zones west (like from New York to San Francisco), its chance of winning would be

-- 40% on the first day
-- 47% on the second day
-- 48% on the third day
-- 50% on the fourth day

That, I assume, doesn't include home field advantage.

The article does imply, near the end, that the first game of three-time-zone trip happened only 160 times in the 10 years of the study. That's a 64-96 record for the tripping team. That works out to about 2.5 SDs away from .500, which is statistically significant. But it depends on the study having controlled for the quality of the teams and home field advantage.

I have a vague feeling that I've seen studies that checked the time-zone theory of home field advantage, and couldn't find any effect. But I'm not sure. In any case, when the study becomes available, I'll take a look at it.

(Hat tip: Freakonomics)

UPDATE: This article has more details, and it seems like the data doesn't support the conclusion. Here's the summary:

Approximately 79.1 percent of the games analyzed (19,084 of 24,133 games) were played between teams at equal circadian times. The remaining 5,046 games featured teams with different circadian times. In these games, the team with the circadian advantage won 2,621 games (51.9 percent). However, 3,681 of these 5,046 games were also played with a home field advantage. In isolating games in which the away team held the circadian advantage (1,365 games), the away team won 619 games (45.3 percent).

From this, we can figure that:

When the road team had the "circadian advantage" -- meaning the home team had to travel more time zones to get to the game -- the disadvantaged home team's winning percentage was 54.7% (746-619), almost exactly the normal home field advantage.

When the home team had the circadian advantage, they were 2002-1679, for 54.4% -- again almost exactly the normal home field advantage, and almost exactly the same HFA they had when the other team had the circadian advantage!
In bold:

Home teams were .544 with circadian advantage;
Home teams were .547 with circadian disadvantage.

So, basically, the study's data show that time zone travel doesn't matter at all. The apparent difference is completely caused by the fact that teams that have recently travelled are more likely to be road teams.



Labels: , , ,

1 Comments:

At Thursday, January 01, 2009 7:33:00 AM, Blogger sexy said...

情趣用品,情趣用品,情趣用品,情趣用品,情趣用品,情趣用品,情趣,情趣,情趣,情趣,情趣,情趣,情趣用品,情趣用品,情趣,情趣,A片,A片,A片,A片,A片,A片,情趣用品,A片,情趣用品,A片,情趣用品,a片,情趣用品

A片,A片,AV女優,色情,成人,做愛,情色,AIO,視訊聊天室,SEX,聊天室,自拍,AV,情色,成人,情色,aio,sex,成人,情色

免費A片,美女視訊,情色交友,免費AV,色情網站,辣妹視訊,美女交友,色情影片,成人影片,成人網站,H漫,18成人,成人圖片,成人漫畫,情色網,日本A片,免費A片下載,性愛

色情A片,A片下載,色情遊戲,色情影片,色情聊天室,情色電影,免費視訊,免費視訊聊天,免費視訊聊天室,一葉情貼圖片區,情色視訊,免費成人影片,視訊交友,視訊聊天,言情小說,愛情小說,AV片,A漫,avdvd,情色論壇,視訊美女,AV成人網,情色文學,成人交友,成人電影,成人貼圖,成人小說,成人文章,成人圖片區,成人遊戲,愛情公寓,情色貼圖,成人論壇


av女優,av,av片,aio交友愛情館,ut聊天室,聊天室,豆豆聊天室,色情聊天室,尋夢園聊天室,080聊天室,視訊聊天室,080苗栗人聊天室,上班族聊天室,成人聊天室,中部人聊天室,一夜情聊天室,情色聊天室,情色視訊

視訊聊天室,聊天室,視訊,,情色視訊,視訊交友,視訊交友90739,免費視訊,免費視訊聊天,視訊聊天,UT聊天室,聊天室,美女視訊,視訊交友網,豆豆聊天室,A片,尋夢園聊天室,色情聊天室,聊天室尋夢園,成人聊天室,中部人聊天室,一夜情聊天室,情色聊天室,080中部人聊天室,080聊天室,美女交友,辣妹視訊

 

Post a Comment

Links to this post:

Create a Link

<< Home