The economic benefits of a World Series championship are "at least twice as valuable as previously thought," writes Seth Stephens-Davidowitz in The New York Times (4/20/14). Traditional analysis suggests that a team’s increased ticket sales would be limited to its championship year and the year following. Seth’s analysis suggests that loyalties made during a winning season — specifically among boys between the ages of five and 15 — will last their lifetimes, roughly doubling the team’s initial revenue boost over time.
This is based on Facebook data, which shows a correlation between when a male fan was born and his team loyalties. The Mets, for instance, "are popular among an unusually high number of men born in 1961 and 1978," who were "both 8 years old when the Mets won the World Series. Fandom is determined by a huge number of factors, like which team your father supports, but winning when boys are young stands out clearly in the data." The same does not bear out relative to female fans — exactly why is not clear.
The implications of such bonds may be applied beyond baseball: "The explosion of big data sets should lead to the rapid development of precise insights into how events at every year of our childhood affect how we think as adults." For example, economists at Yale and Harvard have found that "if you are just old enough to vote in a presidential election, you will be more likely years later to be a partisan of the party you voted for than if you were slightly too young to vote in that election."