Birth Months And Baseball Success

Recently I came upon an interesting piece of data analysis. It's a few years old, so you may already be familiar with it, may already hate it, whatever. I am often slow to learn things. (Like, wow, all the DVD rental stores are closed now! Where am I going to find adults-only video?)

It appears that success in some sports may depend, partly, on your birthday.

Weird-haired author Malcolm Gladwell talked about this in his book "The Outlers" (and in an interview here.) In certain youth sports there's a widely-used cutoff date, before which kids play with an older age group, after which they play with younger. So if you're born right after the cutoff date, you'll have a year's worth of physical development over kids born just before the date.

What surprised me about this (while it's probably obvious to parents/educators) is how I hadn't thought of it even though that essentially happened to me. It happens to a percentage of kids every year, whether or not they sign up for Little League. It's the cutoff date for grade assignment, which varies regionally. I was born just before the cutoff point, and so I was always a little small for my grade until well into my teens. (This didn't matter much for unstructured playground games, but killed me in the dog-eat-dog hellmouth of junior-high PE class.)

Apparently it's most evident in American baseball, Canadian hockey, and European soccer. Greg Spira crunched the numbers from players born post-1950 and found an obvious pattern you can see here; the most MLB players were born in August, the fewest in June/July, and the number decreases fairly steadily for months in between. (According to that article the cutoff date was changed in 2005 from July 31st to April 30th, to better coincide with the start of summer baseball.)

Spira speculates on why there's no such correlation with birth month in the NBA/NFL; a solid answer he gives is that these sports are more popular in high schools, whose cutoff dates are not uniform. I'd also suggest that basketball is the perfect sport for practicing by oneself. It's easy finding a place to practice shooting and/or dribbling; young people sometimes dribble basketballs during walks to school or the store.

Anyhoo, it's something to think about (if it's not old hat to you already. Did I ever mention I finally got rid of my flip phone?) Certainly young people with an easier time in their first experience at a sport are more likely to continue playing it. And players who do well are more likely to receive extra parental support (buying equipment, paying for training programs, etc.)

Or it could just be statistical noise, like ALL THE BAD THINGS HAPPENING TO THE TWINS THIS YEAR. Anyhoo, catch ya later for the game, if it doesn't rain all day in Ohio.