Steele TaylorVanessa Tsong

Erin KnappAlisa Zayas

Hannah Hutton

How Does Coast-to-Coast Travel Affect Performance in Professional Baseball?

Professional baseball teams travel extensively and often from one coast to the other. Due to the phenomenon of ‘jet-lag’ that accompanies travel across time-zones, players are required to compete at what is essentially a different time of day than they are normally accustomed to. Since baseball games are typically played at 7pm local time, traveling to the west to play after being acclimated to the east means players are competing at what feels like10pm. On the contrary, traveling to the east to play after being acclimated to the west means competing at what feels like 4pm. Humans have a daily or circadian rhythm with a corresponding waxing and waning of performance, and the classic pattern is that there is a dip in alertness and cognitive performance in the afternoon (approximately 2-5pm) followed by a second peak occurring in the early evening. We sought to explore whether impaired performance due to travel is more pronounced in one direction of travel versus the other, and in which direction acclimatization occurs more readily with the hypothesis that travel to the east would be more impairing. Performance in baseball, as a batter, pitcher, or fielder is heavily dependent on one’s level of cognitive alertness, reaction time, etc., and not just on pure physical conditioning (like running or swimming), so it is a great candidate for this study. Also, there is a wealth of data because major league baseball teams play 162 game seasons, and typically after traveling they will play a 3 or 4 game series spanning consecutive evenings, thus the process of acclimatization on a scale of days can be observed.

Sampling methods were as follows: we collected data on east coast time zone teams and west-coast time zone teams. All of the data was collected through skillful navigation of We started by recording the controls against which we would later reference our ‘travel’ data: season win-loss record, season home win-loss record, season road win-loss record, and season averages for runs, hits, errors, runs against, and hits against per game. It is important to note that runs and hits are indicators of positive performance (batting), hits against and runs against are indicators of negative performance (pitching), and errors are indicators of negative performance (fielding).The cognitive functions involved in batting, pitching, and fielding are all subtly different and thus each may be impaired by jet lag to different degrees.

We then scrolled through each teams schedule for the 2009 season and identified games that were played after traveling across 3 time zones, either west or east. Raw data collection sheets are attached and demonstrate that all of the data categories listed above were collected per game. Data was collected on games that were played 1, 2, and 3 days after travel. For each team, averages were generated for the games played after travel for all data categories and compared to the season averages for that team. Performance in each category was labeled as “Better”, “Worse”, or “Neutral (within 5%). All of the game data was then pooled and organized into the following categories: games played after travel to the east and games played after travel to the west, games played 1, 2, and 3 days (respectively) after coast-coast travel, games played by east teams visiting west, east teams traveling home the east, west teams visiting the east, and west teams returning west. Mean, median, mode, and standard deviation was calculated for all of the data categories within each respective grouping (attached).

Further data analysis is required but at this point the following trends have been observed:

  1. All teams perform better traveling west vs. traveling east in all categories.
  2. Performance is worse across all defensive categories on day one, and then stabilizes on day 2 and 3.
  3. Fielding errors are significantly worse on day 1.
  4. Performance across offensive categories is stable from day one to day 3, and actually appears to decline gradually.
  5. West teams are better at “homecoming” than east teams in offensive categories, are approximately equal in defensive categories, but have a slight smaller win-percentage.
  6. East teams are much more successful at traveling to the east than West teams, although much of this effect is likely due to the fact that they are returning to their home stadium.
  7. In most categories East teams are BETTER than West teams at traveling west, but the West teams still manage a higher win percentage.
  8. Some teams do much worse than their season averages following coast-coast travel (such as the Oakland A’s), some teams appear to thrive following coast-coast travel (such as the Cleveland Indians), while most are neutrally affected.
  9. Generally defensive performance tends to be worse than season averages, while offensive performance tends to be less affected.

What did we learn? The data collection process was laborious because multiple pages within the website had to be navigated effectively. However once the data was entered into excel it was fairly easy to copy/paste into the various groupings and run analysis on. We inadvertently collected data on more east-coast-time-zone teams then west-coast, although since the West teams tend to have more games in their schedules that follow coast-coast travel the overall number of games collected on West coast teams did not differ significantly. Data collection and analysis could be performed ENDLESSLY and it is important to draw boundaries compatible with the scope of the project. What would be great would be to have a huge database with all games played during the 2009 season… one could then design the proper algorithms to harvest this data in seconds. There are also TONS of confounds that have to be taken into consideration, such as who the opponent is; which players are streaky and which are in slumps or battling injury/illness; the weather; the fact that teams play each other on back to back nights and thus ‘get used’ to each other’; when the team actually traveled (overnight, early morning, etc.); or whether the starting pitcher just had an argument with their wife. Nevertheless we believe that significant trends have emerged that are durable against the above mentioned confounds.