Born on the 4th of July August?
Posted by Doug on October 23, 2006
Let me regale you with tales of my childhood glory on the baseball diamond.
When I was growing up, I played each year in a spring league and a summer league. The spring league was organized by grade (the age cutoff was Sept 1). The summer league was organized by age, with the age cutoff being Aug 1. I was born in late August, which meant that I was always among the youngest people in my grade, but among the oldest in my summer league baseball age group.
So, for example, when I was 14, I was in 9th grade. In the spring I played with 9th- and 10th-graders (the high school JV team), because I was in 9th grade. But in the summer, I could play in two leagues. I played with the 9th- and 10th-graders because that's who I had played with in the spring (and because the summer league allowed for playing up). But I also played with the 7th- and 8th-graders because I was only 14.
I believe that setup was the best of all possible worlds for my baseball development. It gave me the chance to get accustomed to "the big time" while also allowing me to be a star in the younger league. Granted, I'm teaching math and writing a blog instead of playing professional baseball, but I was a pretty good ballplayer back in the day, and I've always believed that my August birthday had a lot to do with it.
My buddy JC Bradbury posted some data over at sabernomics that show that I'm not alone. More major league ballplayers were born in August than in any other month. But the data show more than that. August/September/October birthdays are much more common than May/June/July birthdays, which indicates that it was probably the playing down that helped me more than the playing up.
The idea is summarized in this passage from Steven Dubner, whose work (with Steven Levitt) is what inspired Bradbury to look into it:
Since youth sports are organized by age bracket, teams inevitably have a cutoff birth date. In the European youth soccer leagues, the cutoff date is Dec. 31. So when a coach is assessing two players in the same age bracket, one who happened to have been born in January and the other in December, the player born in January is likely to be bigger, stronger, more mature. Guess which player the coach is more likely to pick? He may be mistaking maturity for ability, but he is making his selection nonetheless. And once chosen, those January-born players are the ones who, year after year, receive the training, the deliberate practice and the feedback — to say nothing of the accompanying self-esteem — that will turn them into elites.
Evidently the same phenomenon is observed, to some extent, in soccer and hockey. This NYT article examines whether or not it might play a role in academics as well.
So I decided to check out the football situation. Among all players currently playing in the NFL (except for offensive linemen, who are not in my database), the birthmonths break down like this:
Month #born
============
1 119
2 111
3 126
4 88
5 91
6 94
7 92
8 129
9 118
10 98
11 113
12 105
The pattern is not quite as clear as it is in baseball (possibly because I have a lot less data), but it nonetheless appears that May/June/July is a bad time to be born if you have aspirations of being a professional athlete. Of course, all this assumes that birthdays are spread equally throughout the year for the general population, which is probably not correct. Still, 40% more current NFL players were born in August than in July, and I seriously doubt that the difference is that dramatic in general.
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October 23rd, 2006 at 5:39 am
Very interesting stuff. Now I have another excuse, as I was born in June. I was always one of the smallest in my class until my senior year in high school (now over 6 ft 3, 220), but then again, school was rather boring and often not a challenge on the academic side, so I cannot imagine what it would have been like with one more year.
As for baseball, I see myself in this. I was good at baseball, particularly hand-eye stuff like playing defensive first base (left handed) and being able to be precise with throwing to spots, but did not throw hard enough, not strong enough and did not hit with enough power. I probably should have been pitching ahead of others on accuracy but not physical enough, and got selected away from pitching early on.
I am already hearing the same debate for my now 3 year old son, born in June, as to when to start him in school. So that we dont move to the absurd and have 8 year olds in kindergarten, ow about this solution for those school districts who have enough students in each grade level? Rather than randomly assigning kids to classes, how about grouping the classes by chrono age? You might have the "old", "middle" and "young" first graders.
As for football, I am a little surprised it shows the distribution. I would guess that the extent to which you see an April/May/June/July lag is going to be tied to when the average kid is starting to play on a legitimate organized team in that sport. For example, baseball, most of us, and most of the pros, probably started playing on a team at age 6. Football, probably not that early. The later you start evaluating and selecting, the less the age differences will show up.
Since your database is primarily offensive skill players, I would be interested in how the position breakdowns went.
Here are my guesses:
RB will show a higher percentage of August or later birthdays, compared to April-June. This is a physical position where the players are identified early on for the most part, and the coach selection process would play a part.
QB is the interesting one. It is the most unpredictable position in recruiting 17-18 year olds for college (one reason why so many eventually good QB's slip through and go to lower tier schools), and is still rather unpredictable by the time they are 22-23. I would guess that most high school QB's would show an age bias, and to some extent college, but that it would disappear by the NFL for this position. I am wondering if the draft busts are more guys who were physically better because of chrono age. Of course, I could be completely wrong and QB could still be the most skewed of all.
October 23rd, 2006 at 7:33 am
Being born in July, NOW i understand why I am not starting for an NFL team right now. What is your excuse, Doug?
October 23rd, 2006 at 8:21 am
Sure I was born in October, but I played "up" my whole life. I went to college at 17, graduated at 21, etc. I never skipped a grade, but just started young. Now I know why I'm just writing comments to a blog and not throwing touchdown passes in the NFL. Thanks, Doug.
October 23rd, 2006 at 11:07 am
Doug, I think you are forgetting to take into account the astrological impact. Being born in late August, I believe you were a Leo.
Leo is the fifth sign of the Zodiac and is associated with creativity and drama. Individuals born under this sign are thought of to have a proud, honest, generous, self-motivated, charismatic, warm-hearted, and enthusiastic character, but one which is also prone to conceit, bullying, rigidity, intolerance, and snobbery. In terms of anatomy, Leo is said to rule the heart, upper area of the spine, and the back in general.
I think that has more to do with your baseball success than anything.
October 23rd, 2006 at 11:13 am
Apparently a similar phenomenon happens in soccer. Half of elite players were born in January, Febuary, or March.
Link to the article:
http://www.nytimes.com/2006/05/07/magazine/07wwln_freak.html?ex=1304654400&en=2cf57fe91bdd490f&ei=5090&partner=
October 23rd, 2006 at 11:25 am
Boy, now if only I could find someone to blame for my lack of height and lack of coordination.
Oh, wait, I can.... My parents...
October 23rd, 2006 at 7:44 pm
How does this compare with the distribution of birthdays across the calendar in the general population? It's not uniform. The appeal of August vacations spikes May birthdays, and December/January holidays yield a September spike. Surely the peaks vary with geography and nationality, so getting the general data for the Dominican Republic might be helpful in analyzing the baseball data.
October 23rd, 2006 at 8:32 pm
@ #7
After a brief googling I found a page with birthday distributions by month:
http://scienceworld.wolfram.com/astronomy/LeapDay.html
I started to trace the references but got bored.
Have at it.
Christian
October 23rd, 2006 at 10:31 pm
Here is somewhat of an answer to my thoughts on QB vs RB distribution. I looked at the birth month of every QB listed on each team page this year (60 total) and the top 2 RB's in attempts for each team (64 total). Here is the distribution per month of each (QB/RB):
Aug- 6/11
Sept- 4/5
Oct- 2/5
Nov- 1/4
Dec- 7/4
Jan- 6/6
Feb- 9/6
Mar- 7/7
Apr- 3/5
May- 4/3
June- 7/3
July- 4/5
Randomness: who would have guessed February as the month with the most current quarterbacks with playing experience? The August cutoff date does have an impact at the running back position, as almost 20% were born in August. The "young" RB's born between May and July may lack quantity, but the quality is there, including LT, Fred Taylor, Frank Gore and Steven Jackson. McNabb is the only QB born in November. And for really random freakiness, Trent Green and Damon Huard were both born on July 9.
April 23rd, 2007 at 9:23 am
You need to determine at what age they graduate high school.
Fred Taylor, Frank Gore and Steven Jackson are the few RB's with May-July b-days. However, they could have been held back for some reason or another and therefore graduation around the age of 19.