Being born early in the year advantageous
Sean Horton, Jess Dixon and Laura Chittle, explain ‘relative age effect.’
The four best junior hockey teams from the Canadian Hockey League have descended on Windsor to compete for the Memorial Cup. The players on these teams are primarily Canadian, with a sprinkling of international players. All of them, irrespective of their hometowns, likely have a number of things in common: talent and passion for hockey, dedicated coaches throughout their development and supportive parents who spent large amounts of time and money nurturing their hockey dreams.
One other thing these players have in common — most were born very early in the calendar year.
This last factor may come as a surprise, but look at the numbers. The roster for the Windsor Spitfires shows that 20 of the 24 players were born in the first six months of the year. A quick check of the rosters for the other three teams shows a similar trend. Of the 99 players listed for the four teams, 73 have a birthday that falls between January and June. December birthdays are rare, with just two, while 16 of the 99 players were born in the month of January.
This phenomenon has a name: the relative age effect. You see it at elite levels of Canadian hockey, but also in other countries and a variety of sports around the world.
Why does this happen? The answers, it turns out, are fairly straightforward. It tends to occur most frequently in culturally valued sports (think hockey in Canada, soccer in England and rugby in Australia) where many children start playing at a young age, and are quickly placed into different levels according to their abilities. The problem is that coaches and parents often confuse talent with age. While they assume that the most talented players are being selected for these elite teams, often it’s just the oldest players.
Hockey in Canada is organized according to the calendar year, so a 10-yearold born in January potentially has a distinct size and strength advantage over a 10-year-old born in December, given the January child is essentially a full year older. This can translate into selection for elite teams, granting the child more ice time, along with more attention from coaches and parents. These opportunities due to small initial advantages can build over time, leading to sustained and meaningful differences years later. Sociologists refer to this as accumulative advantage.
The relative age effect also turns up in other places, notably in education, where relatively younger children tend to struggle in school. Recently, the Toronto District School Board released data showing that the youngest children in kindergarten perform worse than their relatively older counterparts in a number of important areas, including language and cognitive development, emotional maturity and social competence. The board reminded parents that they can delay the start of their child’s schooling if they have a late birthday, and if they feel their child isn’t ready. Indeed, redshirting children to allow them time to catch up, or in some cases, to secure an advantage by ensuring they are the oldest in the class, has become increasingly common throughout North America.
Debate continues to rage with respect to how long these age effects last. Some insist any age advantages or disadvantages disappear by the third grade. Birth dates of those gaining acceptance into Oxford and Cambridge are skewed, however, suggesting that the effects may last much longer, and influence entrance into the world’s top universities. In the case of Oxford and Cambridge, it is the children born from September through December who are advantaged because the cut-off date for school in the United Kingdom is generally Sept. 1. Thus, it is the children born immediately after this date who gain the advantage, leaving those born in April through August under-represented at those institutions.
With respect to hockey, age effects seem to peak at the elite junior levels and then level off slightly in the NHL. They don’t disappear entirely, but they aren’t as strong as they are in the Canadian Hockey League. This has prompted researchers to forward the underdog hypothesis, which essentially states that surviving a system that is stacked against you ultimately makes you stronger.
Cut-off dates for school and sports can vary and seem somewhat arbitrary. The effects, however, seem to be anything but random or arbitrary. Instead, those who are born immediately after the cut-off date, and are relatively oldest as a result, appear to have a systematic advantage.
It’s a complicated issue, one that is not easily resolved, but one thing seems clear. If you want to compete for the Memorial Cup, it helps to be born early in the year.