The birth month phenomena is an interesting occurrence that is applicable throughout society.  While a recent novel I read implied the same was true for baseball, I wanted to take a closer look.  Looking at the birth month of every player that has appeared in a game since 1965, the graph suggests that you’re most likely to become a MLB player if you are born in August.

Among US born players, 12.2% of MLB players were born in August, while only 6.4% were born in July. A discrepancy that big can’t just happen by accident can it?  Not likely.  The reasoning is that the Little League Baseball cutoff date for 55 years (up until 2006) was July 31.

So what does that mean?  A player, for example, born on August 1, 1996 would be playing in the same division as a kid born on July 31, 1997.  Given the cutoff date, the kid born on August 1 is a year older than the kid born on July 31 yet they are playing in the same division.  Thus, the player born in August likely has an advantage in size, strength and maturity.  Thus players born in August may be more likely to get picked for All Stars and more likely to get advanced practice time to become an even more successful player.

Interestingly, in 2006 Little League changed the cutoff date to April 31, so if you want your kid to have a leg up on the competition, a May birthday will be most beneficial.

So if players born in August are more likely to become MLB players, do they perform better at the Major League level?  Stay tuned for Part II in a few days.

Data Source: Sean Lahmans’ baseball1.com