If you have ever watched a group of eight or nine year olds training together and wondered why some look so much more physically developed than others, the Relative Age Effect is often part of the explanation. It is one of the most consistent findings in youth sport research, and it has a real impact on how young footballers are identified and selected in England.
Understanding it does not change the system overnight, but it can help you make more sense of what your child is experiencing and keep their development in perspective.
Understanding the Relative Age Effect
The Relative Age Effect (RAE) refers to the performance and selection advantages that tend to benefit children born earlier in an academic or sporting selection year compared to those born later in the same year.
In English football, the academy selection year runs from 1 September to 31 August. A child born on 1 September is nearly a full year older than a child born on 31 August of the same selection cohort. In adult terms, twelve months is unremarkable. In childhood, twelve months can mean significant differences in height, strength, coordination, speed and emotional maturity.
When coaches and scouts assess eight, nine or ten year olds, those physical and developmental differences can look a lot like talent. A boy born in September may appear stronger, more dominant and more composed than a boy born the following July. The September-born child has not necessarily worked harder or been better coached. He is simply older.
How Football Academies Create Relative Age Advantages
Academy football groups players by age band. Foundation Phase covers Under-9 through to Under-11. Youth Development Phase runs from Under-12 to Under-16. Professional Development Phase covers Under-17 to Under-21. Within each age group, every player in the squad can be up to twelve months apart in age.
Several factors compound the initial physical advantage:
More selection opportunities. At trials and scouting events, physically advanced players are more likely to catch the eye. This is not a deliberate bias, but an assessment challenge. Coaches making quick judgements across large groups of children will often respond to what looks like maturity, composure and dominance. As well as the Relative Age Effect, children also develop and mature at different rates.
More coaching attention. Players who appear more capable often receive more positive coaching feedback and more time with the ball in training sessions. This reinforces their development advantage. From my own experience, in competitive teams, the better players often get more opportunities, whether that is as simple as minutes on the pitch or the coach elevating their status.
Greater confidence. Winning individual duels, scoring goals and being praised by coaches builds confidence. Early developers accumulate these experiences more readily. Later developers can become withdrawn or lose confidence before their physical development has a chance to catch up.
Longer time in the system. A child selected at Under-9 who stays through the Foundation Phase builds footballing habits and technical knowledge over several years. A child not selected until Under-12, or not at all, starts later and with fewer structured development hours.
Parents comparing different routes into academy football may also find our guide to development centres vs academies useful for understanding how these systems fit together.
What the Research Says
The evidence for the Relative Age Effect in English football is well established. Studies examining academy player cohorts have consistently found that players born in the first quarter of the selection year (September to November) are significantly over-represented compared to those born in the final quarter (June to August).
Research published in sports science journals and referenced by UK Coaching has highlighted this pattern across multiple youth sports, with football among the most affected. The Premier League's own research into academy development under the Elite Player Performance Plan (EPPP) has acknowledged relative age as a factor in youth recruitment.
A study examining birth date distributions among English academy players found that, across 1,003 academy soccer players from 23 UK professional clubs, 45.0% were born in the first quarter of the selection year compared with only 9.8% born in the last quarter. The effect tends to be strongest at younger age groups and often diminishes as players reach the late teens, when physical maturity gaps narrow.
It is worth noting that the evidence is not entirely uniform. Some research suggests the effect varies between clubs, between positions and between different levels of the game. The effect in girls' football has been studied less extensively than in boys' football, though findings suggest a similar pattern exists, particularly in more competitive environments.
For more context on how the EPPP structures academy development, our guide to what EPPP means for parents explains the system in plain terms.
Why Relative Age Matters for Parents
The most important thing to understand is that selection decisions in youth football are not purely about talent. Physical maturity plays a significant and often unacknowledged role, particularly at younger age groups.
This has several practical implications.
A child who is not selected at Under-9 or Under-10 may be developmentally behind peers at that moment, not permanently behind them. Development timelines in childhood vary considerably. A child who looks average at nine may look exceptional at fourteen, once physical maturity gaps have narrowed and technical habits have accumulated.
Equally, early selection is not a guarantee of long-term success. Children who enter academies partly because of physical advantages may find those advantages erode as peers catch up. Release rates across academy pathways are high, and many children selected at younger ages do not reach the scholarship stage at sixteen.
Our article on late developers in football explores this in more detail and explains why the window for development is much wider than early selection suggests.
Does Relative Age Affect Professional Football?
The evidence here is genuinely interesting. At the professional level, the Relative Age Effect tends to weaken or even reverse. Some research has found that players who make it to professional football despite being born later in the selection year show greater resilience, stronger intrinsic motivation and, in some cases, higher technical quality than their earlier-born peers.
The reasoning is that late-born players who survive youth football have had to work harder, adapt more and compete against older opponents. Those who come through despite the disadvantage may carry qualities that serve them well at the highest level.
Several successful professional footballers are known to have been born in the final quartile of the selection year. This does not make a late birthday an advantage. However, it does challenge the idea that early selection is a reliable predictor of professional potential.
The broader point is that youth football cannot reliably identify future professional players at eight or nine years old. Many factors beyond physical maturity, including decision-making ability, attitude, learning speed, resilience and technical quality, matter far more over the long term than early physical development.
What Parents Can Do
Understanding the Relative Age Effect is useful, but parents cannot control the selection system. What you can influence is how your child experiences their development.
Avoid direct comparisons with physically advanced peers. If your child is smaller or less physically imposing than others in their group, this is often a timing issue rather than a talent gap. Making comparisons rarely helps confidence.
Prioritise development over selection. A child who is learning, improving and enjoying football is on the right track, regardless of whether they are in an academy. Development centres, grassroots clubs and good coaching environments all provide genuine development opportunities outside formal academy structures. Our guide to whether development centres are worth it covers this honestly. I’ve found that, for some children, being physically behind has benefited them longer term. In the younger year groups particularly, the boy who physically matures early might have a hard shot and score goals. But they begin to rely on it and don't need to develop their overall game. The smaller boy has to move the ball quicker and work on their skills because they cannot simply barge people off the ball. When they catch up physically, they may become a more well-rounded footballer who is not solely reliant on physicality.
Seek appropriate challenge. Sometimes a child who is not yet physically competitive in one environment will thrive in another. This is not a failure. Finding the right level and environment matters more than chasing the most prestigious pathway available. For my own son confidence (and having the confidence of the coach) is a huge thing.
Give it time. Many parents pull their child from football or accept that academy football is not for them based on assessments made when their child was eight or nine. The picture at thirteen or fourteen can look completely different.
Talk to coaches honestly. If you are concerned your child is not being assessed fairly, a calm, constructive conversation with a coach about development rather than selection is usually more productive than pressing for explanations about why your child was not picked. Try to ask questions that help you understand what they might need to work on, whether that is a specific technical area or decision-making area. You won't argue the coach into picking them, so you need to use it as an opportunity to get feedback that can help your child.
Frequently Asked Questions
Does the Relative Age Effect only affect boys' football?
No. Research suggests a similar pattern exists in girls' football, though it has been studied less extensively. In girls’ football, while present, it is generally weaker and less consistent than in the boys’ game, and the effect appears strongest in central positions. A study of 1,634 profressional players from the top 5 European leagues found it particularly pronounced among goalkeepers, central defenders, midfielders and centre forwards during the talent identification phase.
Can academies correct for the Relative Age Effect?
Some clubs have introduced bio-banding, which groups players by physical maturity rather than chronological age, to try to create fairer assessment environments. Bio-banding is not universally used and its application varies considerably between clubs and age groups.
My child was born in August. Does that mean they will never get into an academy?
No. August-born players do reach academies, develop through youth football and reach professional level. The RAE describes a statistical tendency, not an individual fate. It means the odds are less favourable at younger ages, not that the pathway is closed.
Should I ask a club what month players in their academy squads were born?
You can, but most clubs will not provide this information. If a club is aware of relative age bias and takes steps to account for it in their assessment process, that is worth knowing and worth asking about.
At what age does the Relative Age Effect start to matter less?
Research generally suggests the effect weakens as players move into their mid-teens and physical maturity gaps narrow. However, because earlier-born players have often had more development time in the system, some of the advantage can persist even after physical differences disappear. As a parent, the best thing you can do is try to ensure that your child has high-quality coaching and development. If they are in an environment where they are stretched and getting good-quality technical work, they will be in a good position once they catch up physically.
