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
1 hour: CHA, CHN, MIL, TEX, HOU, MIN, KCA, SLN
0 hours: all others
I'm now going to go back and update the other two posts with the correct numbers.