February 1, 2017
Blame it on the Plane
Last week, there was an article making the rounds about a baseball study that was published in an actual scientific journal! The study, published in the Proceedings of the National Academy of Science (PNAS) and written by researchers Alex Song, Thomas Severini, and Ravi Allada of Northwestern University, looked at major-league games from 1992-2011. They specifically looked at the effects of travel across time zones for teams.
It makes sense that travel might impact a player’s (and a team’s) performance. MLB teams are located in four different time zones, and when a team goes from New York to Los Angeles they might find themselves in a position where their bodies think it’s 7:00 pm and time to start tonight’s game, but the clock thinks that it’s 4:00 pm. The clock usually wins that debate.
While I always appreciate “real” scientists taking up baseball as a medium, we also need to make sure that the work is high quality. I am not enough of an expert on circadian rhythms and sleep adjustment to pass judgment on their contention that a human being needs one day per time zone crossed to fully adjust to the new time, but that sounds reasonable and they have some references, so I will accept it as valid.
The problem is everything else that they did.
The full article (which can be read here) says that the researchers used game logs from Retrosheet (sounds good so far) and figured out how many time zones teams had recently traveled over and how much time had passed since they did so. Based on the idea of one day per time zone of adjustment (that is, going from New York to Los Angeles crosses through three time zones, and so would take three days to fully adjust to), they classified teams into two groups—either 2-3 hours offset or 0-1 hours offset.
On the first day of their trip out to LA, our team traveling from NYC would be three hours offset, but by the third day, they would be down to one hour. The researchers did explicitly account for scheduled off days, which the schedule-maker mercifully usually puts in front of a big trip. However, they then did something rather strange, or at least if they didn’t do something strange they explained it in a strange way.