Can Your Birthday Help You Play Major League Baseball?

As a follow up to my last blog, 6 Ways That Numbers Can Lie To Us, I wanted to investigate a fascinating phenomenon about how one’s birth month relates to success in professional sports. The book Outliers by Malcolm Gladwell found that a disproportionate number of Canadian-born National Hockey League players were born in the first few months of the year.

I wanted to see if a similar pattern held true for Major League Baseball players, so I did some quick analysis. The chart below shows the birth month of every U.S.-born MLB player who played from 1965 to 2012. The results and implications are pretty interesting.

What Does This Chart Say?

Based on a sample size of 6,449 MLB players, 11% were born in August compared to only 7.1% in July. September and October also have relatively high percentages. Furthermore, the overall rate of US births is more evenly distributed across all 12 months. So why are so many professional baseball players born in August-October?

Why Is This Happening?

This could well be an example of a self-fulfilling prophecy. In the United States, the Little League Baseball cutoff date (until 2006) was July 31st. This means that kids born on, say, Aug. 1, 1990 were playing in the same league as kids born on July 31st, 1991. In other words, the August babies were almost 1 year older than those July babies, but playing on the same team. For little kids, that age gap can mean a huge difference in physical maturity and achievement on the field. When it comes time to pick the all-stars and tournament teams, the older players will often be selected because they are simply the biggest and strongest. This puts them onto an “accelerated” path, which includes better coaching and training, more practice time and more competition against good players. Many years later, those kiddie All-Stars actually do become the best players because they’ve been placed in the best possible environment to succeed since they were little.

Note: In 2006, Little League Baseball changed the cutoff date to April 31, so in a few years we’ll be able to refresh the data and see if there’s now an advantage for kids born in May 🙂 .

How Does This Apply To Business?

While technology can do incredible things, it’s the human element that still matters most. In this case, an arbitrarily chosen end point (the cutoff birth date) had a long-term, systematic impact on the success of a group of people. Similarly in business — as we enter the era of big data — your information will always be bound by specific parameters.

Make sure to always question whether those parameters are arbitrary or based on sound analysis. It could have a significant impact on the quality of your decisions.

The other important lesson for business is that great employees are made, not born. Do everything you can to put them in a position to succeed, and you can reap the benefits.

Please feel free to comment if you agree, disagree or have questions. Or contact me via Twitter @ChrisKimSAP.