Age Bias in Youth Football
Coaches and scouts typically assess each player’s ability relative to others born in the same year, and use this comparison to select individuals for teams and other development opportunities. For example, players on a current under-12’s will have all been born between January and December, 2012.
Is this kind of comparison really fair? For an early or pre-teen, the difference between being born in January versus December is massive—around 10% of their life so far. Adolescence is a time of dramatic physical change, so older players in a year cohort are often larger and more physically developed and tend to look “better” on the field as a result. This is known as the Relative Age Effect and is the most pervasive systemic bias in team sports globally.
It’s not intentional—but it happens!
If selection based on year cohorts is fair, then teams should have a pretty even distribution of birthdays across the year—like what we see in school classrooms. Yet our research shows that 50% of all players in elite youth academies are born in the first three months of the year, while fewer than 10% are born in the last three months of the year.
The Age Effect Bias disadvantages all kids.
Obviously, the Age Effect disadvantages younger, smaller or slower-to-develop players within a cohort—simply because they don’t look as big or fast on the field at that moment in time. By the time they mature to the same size as their teammates, many of these kids have already been left behind.
However, the Age Effect also creates problems for the older, more physically-developed players in an age cohort. Players within elite academies born in the first three months of the year are actually 8x less likely to become professionals than those academy players born later in the same year. These are startling numbers. What’s happening? Older or larger players in a cohort learn to rely too much on their physical advantage for success and often stagnate later in their junior careers.
