Well I just pulled out my copy of Outliers and I was mistaken. Baseball does have a bias but the cut-off is August 1st. August is a much more common birth month than July in the Major Leagues. It’s not to the level of ice hockey but it’s there.
It’s actually basketball in the US where there isn’t an effect.
Munch has already mentioned the fairly rigid pitching schedule in the major leagues, as well as the fact that pitchers have obligations even on days when they’re not starting a game.
But i have a more general question for you:
How many adults do you know who would ask for a day off work on their birthday? Because i don’t know a single one. As an adult, the idea that my birthday requires going out of my way to get off work is completely alien to me. I’ve gone some years barely even remembering that my birthday was coming up.
That’s not to say that the day passes completely unobserved, and on my 30th birthday i had a big party with a bunch of friends, but the celebrations are scheduled around other things.
Now I’m curious about why basketball doesn’t have the effect
My first guess is that success in basketball is so strongly correlated with height that having a slight head-start in the early years matters a lot less by the Jr. High and High School years. If you get to High School and you’re 6’6", no one cares that you weren’t great at basketball before. If you invest some time, you’re going to have a huge advantage over all but the very select few of the kids who pour their heart and soul into basketball but never grow tall enough.
He said that there are so many basketball courts available in gyms and parks that anyone with the desire can play anytime and that you only need a few people for a game. This is not true with ice rinks and baseball fields.
He does mention height and basketball in a different discussion but that’s a different hijack to this hijack. Basically, you need to have talent and be above a certain height (6’6"?) to make it (obviously there are exceptions.) Once you are above that cutoff, there isn’t a correlation between height and success.
Gladwell starts out making the point that coaching counts. He said that in hockey, kids were coached at a higher, more beneficial level relative to their age if they were young for their level based on birthday. Therefore the argument that it’s so easy to get basketball court time so it doesn’t conform to the same pattern doesn’t wash, especially because it is Gladwell himself making the argument. And this argument is literally a footnote.
Gladwell is a good writer but he is not a research scientist. His work is not scholarly; he is a journalist. Take it with a grain of salt.
From my applied mathematics degree days and statistics classes many years ago, I remember a counter-intuitive statistical fact about sharing birthdays. The odds of your birthday being on any given day is 1/365, but for *any two randomly-selected people to share the same birthday you only needed about 25 or 30 - and I can’t remember the exact number but it’s about that - people for the chances to be better than 50% that two of those people share the same birthday.
As for pitchers starting on their birthday, Barry Zito did that yesterday. He won, so as a Giants fan I’m grateful for that.