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A young woman doing a box jump workout at the gym.istockphoto/Handout

Just over a decade ago, Malcolm Gladwell made a modest proposal. “If Canada had a second hockey league for those children born in the last half of the year,” he wrote in his bestselling book Outliers, “it would today have twice as many adult hockey stars.”

The suggestion was based on a phenomenon called the “relative age effect.” As a kid, being a few months older than your peers matters – and in activities where talent is identified and streamed early, that difference can determine your ultimate fate. An influential 1985 study, for example, found that NHL players were more than twice as likely to be born in January as in December – a telltale sign of wasted talent among those born late in the year.

Gladwell’s proposal made a big splash, including anecdotal reports of parents timing their pregnancies for maximum advantage. But in the years since then, researchers have found a more nuanced picture in which January isn’t always better. At a conference held at York University last fall, the world’s leading experts in the field gathered to assess what we now know about relative age effects – and what we should (or shouldn’t) be doing about it.

For starters, splitting minor hockey into multiple leagues is probably more trouble than it’s worth, says York University professor Joe Baker, who co-hosted the conference along with University of Windsor researchers Sean Horton and Jess Dixon.

“I think [the relative age effect] is more than an interesting cocktail-party phenomenon,” Baker says. But focusing on a narrow fix for birthday bias misses the underlying issue: “It’s a sign and a symptom of the problems that we have with early sports selection, which is we overemphasize things like speed and power and physical outcomes.”

Now that the effect is well-known, it’s clear that simply making coaches and scouts aware of the relative age bias isn’t enough to eliminate it. But there may be simple tweaks that can help.

David Mann, a researcher at Vrije Universiteit Amsterdam, has shown that simply having young soccer players wear bibs numbered according to their relative age enables talent scouts to make judgments unclouded by age. Swimming Australia, meanwhile, has developed age-graded conversion tables that allow young swimmers to assess their race times relative to their exact age.

It’s also clear that sports is just one area where subtle month-of-birth differences can have lasting effects. Other researchers have found that relatively older children have higher academic attainment, are less likely to be diagnosed with ADHD, and even have lower likelihood of committing crimes as teens.

That diversity creates opportunities, says Luca Fumarco, a researcher at the National Institute of Statistics and Economic Studies in Luxembourg. He has found that relatively younger children have fewer friends and spend less time with them outside school. But since different activities have different age cutoffs – in Luxembourg, for example, school year has a September cutoff while soccer has a January cutoff – parents can encourage their children to participate in a variety of activities so they’re not always the youngest, he says.

Perhaps the most interesting twist in the relative-age literature is the emerging evidence of an “underdog effect,” in which the younger kids who do make it to elite levels end up doing unexpectedly well.

Some of the first hints came in a 2007 study where Baker and a colleague found that NHL draftees between 2000 and 2005 were more likely to be born early in the year – but draftees born later in the year were more likely to be selected in the early rounds.

Subsequent research has turned up similar effects in other sports, too, and a 2017 study by Fumarco and his colleagues found that among the top 10 per cent of NHL players, those born in the last quarter of the year scored nine more points and earned 51 per cent more pay than those born in the first quarter of the year. Struggling against slightly older athletes, it turns out, may help talented youngsters develop physical or psychological skills that serve them well when their growth eventually catches up with their peers.

One response to these findings would be to organize minor sports leagues by size and physical maturity, as U.S. minor football leagues do, says Benjamin Gibbs, a Brigham Young University researcher and co-author of the 2017 study. “This could get dicey and weird,” he admits, “but I think that something like this is a logical extension of the findings, [and] a way to avoid the wasted-talent phenomenon.”

Better yet, says Baker, selection and streaming should be delayed until athletes are as close to mature as possible. In 2013, he helped develop guidelines for English rugby that delayed specialization and selection for national-team programs until the age of 16 – an excellent model, he says, but one that would be hard to impose in decentralized sports like hockey and soccer where independent teams select and stream much younger children.

Ultimately, the most important message – the one that Gladwell, too, was trying to convey a decade ago – is that what looks like natural talent is sometimes an illusion created by arbitrary circumstances and opportunities. And, conversely, that means lack of talent may also be a temporary illusion, so we should avoid closing doors prematurely.

“I get asked by parents all the time, ‘How can I tell if my kid has talent?’” Baker says. “I never start with ‘How tall are they?’ It’s always ‘Do they love sport? Are you having to drag them out of bed, or are they driving the interest and intensity?’ And if the answer is the latter, that’s probably as good an indicator of talent as we have.”

Alex Hutchinson is the author of Endure: Mind, Body, and the Curiously Elastic Limits of Human Performance. Follow him on Twitter @sweatscience.

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