Malcolm Gladwell’s book, “Outliers” (2008) popularised the concept of the RAE (Relative Age Effect) to the broader community by referencing hockey studies completed in the mid-1980s.

Roger H. Barnsley, Paula E. Barnsley, and Angus H. (Gus) Thompson, examined birthdates of players in the Canadian National Hockey League. The Canadian junior hockey league, had an overrepresentation of athletes born in the first few months of the year, particularly January, February, and March.

Their research, concluded that something as arbitrary as a birth date could influence an athlete’s potential trajectory, and since then, other researchers have also replicated and expanded on the original studies. Analysing the distribution of birth months of players in various leagues and examining the factors that contribute to the RAE.

In sports, January 1st is used as a standard cut-off date for age groupings. Children born early in the year are older and more physically developed when youth sports teams are formed. This small advantage can create a cascading effect of opportunity over time.

Coaches and managers, take more notice of the physically mature players, offering them more playing time in games and advanced training opportunities.

Over time, their skills improve faster, which leads to selection for elite teams. What starts as a minor age difference when athletes are young, becomes a significant developmental advantage over time.

This phenomenon, extends far beyond hockey. Soccer, baseball, and other competitive sports show similar patterns. Revealing how systemic structures can inadvertently create unequal opportunities.

We need to reconsider how we identify and nurture athletic talent. Success is not merely about individual skill, but also about the sometimes invisible structural advantages or disadvantages that can shape an athlete’s journey.