Outliers – Birth Months and Elite Sportspeople

Are birth months the be-all and end-all of predicting sporting success?

Recent conversations with parents about kids’ sporting teams and age groups got me thinking (again) about how large the gaps in development are between young kids. In turn, this had me circling back to the ‘relative age hypothesis’ (RAH), or the idea popularised by Malcolm Gladwell in his excellent book ‘Outliers’, that children with birth months in the first part of the year were more likely to be successful in sports (hockey, in his example). But is it always the case?

If you started and stopped your analysis at Bernard Tomic (October), the youngster who not only tanks but wears tank tops, then you might say the case is closed! Shahid Afridi might be a different case altogether because his birth date has a standard deviation of +/- 5yrs, but there’s only a 10% chance of that …

But think about it. The difference between a 5yr old and a 6yr old is 20%. That’s a massive difference, equating to a Yr 5 student pitting themself against a Yr 7. Or, a 14yr old trying to mix it with a (nearly) 17yr old. These comparisons highlight quite clearly that a January baby versus a December baby are going to be at very different stages of development in their formative years, even being in the same class at school.

If this little June baby Dr was familiar with the RAH at age 4 ½, he wouldn’t have played sport at all. My sporting ability and fate were already sealed, according to the theory. I may as well have hopped on the roof with a Bacardi breezer and a dole check (or a pineapple donut and Chocolate Moove back in the day).

Thank goodness it’s not the ‘iron rule’ as described by Malcolm Gladwell. And I did relatively well at a range of sports to prove that a mid-year baby need not succumb to a meaningless statistic.

Think of where The Storm might be without their Big 3 (Cronk a December baby, with Slater and Smith late June). Wally Lewis and Sam Burgess, both outright champions, seem to have coped with being a December baby too, much like Tiger Woods. And the athlete of all athletes, Sonny Bill Williams was an August baby, as was the 8 out of 10 on the Morley-scale Paul Gallen.

So is the relative age hypothesis just a recognition of percentage differences in development that is substantial at young ages, but which fades with time and actually reverses? It seems that way.

It turns out that it is all a matter of framing (what isn’t?). A bit like John Howard many years ago setting the Republic Referendum question as including the ‘type’ of Republic model as well. If he had just asked ‘Do You Want a Republic?’, there’s no doubt the answer would have been Yes, and then we could have determined the actual model over time. Similarly, how is success defined in terms of the RAH?

If making a major junior team is the definition, then yes, the RAH does a pretty good job. Remember, we’re talking about young children where time gaps are more significant than in later years. Consistent with this fact is that the teams Gladwell analysed in his book showed a very different, and lower, birth month advantage just 3yrs later.

But if the definition of success is making the NHL (or NRL for that matter), the RAH is diminished in a major way. It even reverses at the elite levels as another study has shown. And that makes sense too – the older fellas giving way to those entering the prime of their careers in terms of age and experience.

Layman science is seductive and engaging. It’s certainly easy and fun to absorb. In fact, it’s not just layman science that is so intriguing. It’s any subject, really, where a perceived authority figure outlines (usually one side of) a case, makes some suggestions based on a set of data, and reaches a conclusion that sounds plausible.

But, like food, it’s always best to check the labelling and ask a few questions.

Anyway, this is just a quick break in transmission to keep me occupied now that NRL 360 is over.

Normal service resumes tomorrow with a barrage of ‘non-spun’ statistics for the Manly-Tigers clash, and the game of the week, Bulldogs- Rabbitohs.


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