Sunday, July 06, 2008

Do teams play worse after a time zone change? Part IV

I realized I made a mistake in my last two posts on the time-zone study … I had three of the teams in the wrong time zone. The updated results still aren't signficant, but I'm going to go back and correct the numbers in the previous two posts.

I found this out because Dr. Winter, the study's author, was kind enough to send his own results for comparison. These are the home team's record with various amounts of "circadian advantage". (The circadian advantage occurs when one team has less time-zone lag than another, where the lag is the number of time zones crossed, minus the number of days since the crossing. So if you flew from Seattle to Chicago two days ago, you have a disadvantage of 1 – you crossed 2 time zones, but had 1 day to recover.)

Here are Dr. Winter's numbers:

Home record/3-hour circadian advantage: 77-48 (.616)
Home record/2-hour circadian advantage: 487-426 (.533)
Home record/1-hour circadian advantage: 1438-1204 (.544)
Home record/0 circadian advantage: 10207-8872 (0.535)
Home record/1-hour circadian disadvantage: 577-465 (.554)
Home record/2-hour circadian disadvantage: 152-133 (.533)
Home record/3-hour circadian disadvantage: 15-20 (.429)

The only sign that there's some effect is in the 3-day case. Home teams that just got back from the other coast went only .429; when the *visiting* team just arrived from the other coast, the home team beat them up to the tune of .616. However, neither of those two results is statistically significant – both are between 1 and 2 standard deviations from the mean.

My numbers are still a bit different from Dr. Winter's, but not much different – the conclusions are the same. And Dr. Winter did say that these numbers were adjusted since the original study and analysis is continuing.

For the record, here are the time zones I used (Retrosheet abbreviations):

3 hours from east: LAA, OAK, SFN, LAN, SDN, SEA, ARI, ANA
2 hours: COL
0 hours: all others

I'm now going to go back and update the other two posts with the correct numbers.

Labels: , ,


At Tuesday, July 08, 2008 1:54:00 AM, Anonymous Anonymous said...

It'd be very interesting to see this with more data - the 3-day effect looks, on paper, very compelling (albeit not statistically significant.) Could this possibly be a part of home field advantage rather than a result?

At Tuesday, July 08, 2008 1:57:00 AM, Blogger Phil Birnbaum said...

I think one of the other posts (part III?) gives the 3-hour breakdown for other decades. Nothing as extreme as this, though.

At Saturday, July 12, 2008 8:17:00 PM, Anonymous Anonymous said...

Hi, I just came across this blog. It looks very interesting. I'm an Economics Ph.D. student and I also post on a Phillies blog called "The Good Phight", and I posted recently about Homefield Advantage there.

One thing that I noticed is that there seems to be a significant different in between how teams play at home against division opponents and against out of division opponents (out of division-- significantly more homefield advantage), and I also looked at some interleague games.

It seems that there is a large effect of being familiar with a stadium as well as an effect of travel distance as well. I'd love to know if home teams perform better the first game of a series, but I am not a programmer and don't have much of a sense of how to obtain this data. Do you have any knowledge about this?

If you are interested, here is my post:

My main results were:
1. There is no persistence in which teams have larger homefield advantages
2. Weaker teams have larger homefield advantage—or more likely, disadvantage away from home
3. Homefield advantage sets in particularly during the first and last innings
4. Home teams succeed at
1. Hitting more homeruns
2. Striking out less
3. Walking more
4. Getting hits on balls in play
5. Pitching complete game shutouts
6. Allowing fewer runners to reach on error
7. Stealing bases more successfully
8. Getting hit by more pitches
9. Hitting triples
10. NOT especially at hitting doubles, but at hitting extra base hits on balls in play overall
11. Picking off opponents’ runners
5. The largest homefield advantage in order occurs from largest to smallest in:
1. Interleague cross-division games
2. Interleague same-division games between non-“rivals”
3. Non-interleague cross-division games
4. Non-interleague same-division games
5. Interleague “rivals” games
6. There is no strong tendency to gain or lose homefield advantage when moving stadiums—but a very slight tendency to lose homefield advantage (though statistically insignificant)
7. Home teams have more success in close games than blowouts
8. Home teams have more success in low-scoring games


Post a Comment

<< Home