There’s been much research and writing over the years about the positive and negative affects of birth month on various aspects of life, few as well known as Malcolm Gladwell‘s 2008 bestseller Outliers: The Story of Success. Now comes word that having been born at certain times of the year might help or harm your chances of becoming a boss. (Which means, once again, that it’s all your parents fault if you fail!)First things first, for those unfamiliar with what is variously called the “relative-age effect,” “birth-date effect,” “month of birth bias” or “season of birth bias”: The basic idea is that kids born just before the cutoff date for an academic year or sports age division are at a disadvantage because they can be nearly a full year younger than some of the other children in their group. As a result of being intellectually or physically less mature, the theory goes, such kids are less likely to excel from the outset, which makes it less likely that they’ll get the particular kind of attention and feedback that tends to flow towards high achievers. Similarly, they’re less likely to be chosen for leadership roles, such as speaking at assemblies or captaining a team.
That brings us to a new study published in the December issue of the journal Economic Letters, co-authored by Qianqian Du of Shanghai Jiao Tang University in China, Huasheng Gao of Nanyang Technological University in Singapore, and Maurice D. Levi from the University of British Columbia’s Sauder School of Business. Knowing that most academic year cut-off dates fall between September 1 and January 1—thus making kids born in the summer months most likely to be the youngest in their classes—the three researchers theorized that June and July babies would be less likely to grow up to become corporate CEOs, since those roles reflect a long journey of competition and achievement, which should be affected by the relative-age effect if it truly exists. (Outcomes for kids born in August, they speculated, would be affected by the decision of some parents to hold them back, making some the oldest in the next year’s class.)
To test their theory, the trio collected as much birth-date info as they could for the CEOs of S&P 500 companies between 1992 and 2009, eventually able to identify accurate birth days for 375 such suits. And wouldn’t you know it, their theory proved to be both true and statistically meaningful: After accounting for trends in U.S. births (more people are born in some months than others) and plain old randomness, the study authors found that the two months produced one quarter to one third fewer CEOs than you’d expect from a normal distribution of bosses across months. That is, although 8.16% of U.S. births happen in June, only 6.13% of CEOs were born in that month, while a mere 5.87% of CEOs were born in July, despite 8.75% of the U.S. population being born that month. Says Levi: “Early success is often rewarded with leadership roles and enriched learning opportunities, leading to future advantages that are magnified throughout life.”
Or, as Gladwell puts it in Outliers,”If you make a decision about who is good and who is not good at an early age; if you separate the ‘talented’ from the ‘untalented’; and if you provide the ‘talented’ with a superior experience, then you’re going to end up giving a huge advantage to that small group of people born closest to the cutoff date.”
All of which raises the question: If being born in June and July augurs poorly for your chances of landing in the corner office, what birth months are most likely to set you up for life as a big cheese? The answer suggests there’s something to the idea that the relative-age effect influences the ranks of CEOs. Four of the five months with the highest percentage of CEOs are within three months of at least some possible academic cut-off date from September 1 through December 31—meaning children born in those months have a higher probability of being among the oldest in their class. The top 5 CEO-producing months are: March (12.53%), April (10.67%), November (10.67%), January (10.13%), October (9.87%).
Alas, this doesn’t tell us much about the race for America’s CEO. Mitt Romney, a March baby, was destined at birth for the corner office, and he fulfilled that destiny several times over. President Obama, born in August, was surely one of the youngest kids in the 1966-67 Noelani Elementary School kindergarten class, but he seems to have gotten the attention and feedback he needed to fulfill his leadership potential.