Understanding the relative age effect in youth soccer

Relative age effect (RAE) is a phenomenon in which being born at a certain time of the year offers someone an advantage, usually in sport or academics.

In simpler terms, it means those that are older in a group usually have an advantage due to being more developed physically, emotionally and cognitively.US Soccer is allowing members to choose from three possible roster formation cycles: 

How does it show up in youth soccer?

Whether soccer teams are formed by players in the same birth year, school year, or any other way of splitting age groups, relative age effect is present.

Though this is by no means a blanket rule, more often than not, oldest players in the group are likely to be taller, stronger, faster, and more advanced in their learning as they are further along their biological journeys.

This becomes especially relevant at certain points in a player’s growth, namely peak height velocity (PHV), colloquially known as the ‘growth spurt’. This typically occurs between the ages of and 12 and 14 in boys and 10 and 12 in girls. Older players are likely to hit their PHV, and physical maturity, faster.

This might translate in them performing better, or being seen as ‘better’ or ‘more successful players’ when compared to younger players in the group. This can lead to a higher dropout rate for younger players.

This generally evens out at the age of 17.

Relative age effect can have an impact on how we as coaches, and soccer as an industry, view, identify and work with talent. And this impact is something that we must be aware of.

How should it inform my coaching?

Relative age effect should be something that all coaches are aware of. A level of understanding around the subject will only allow us to better support are players. As a coach, there are a number of things you can do.

1. Keep it front of mind

You know about it now, so make sure it forms part of your thinking. It’s another layer of knowledge, alongside other layers such as your tactical knowledge, or your knowledge about how to work with young people, that can and should be used to inform your approach.

2. Challenge your bias
Prefer a player because they’re quicker or faster? Could it be because of their age? Are they always going to be that way? What technical ability do they have?

Thinking about a player as being ‘slow’ or ‘weak’ or ‘off it’? Could it be because of their age? Are they always going to be that way? What technical ability do they have?

3. Work with the individual
See each player as an individual. Each player has a completely different story – a different beginning, home life and motivations – a different personality, a different way they like to be worked with, and a different playing style and strengths as a player.

4. Review the make-up of your squad

What players do you have in your team, and where do they rank in terms of age? A common method of assessing player ages is splitting them into quarters.

In England, where teams are grouped by school year, with a September 1 to August 31 birth time frame, quarters are defined as follows:

• Q1: Players born September 1 – November 30
• Q2: Players born December 1 – February 28
• Q3: Players born March 1 – May 31
• Q4: Players born June 1 – August 31

In the US, where teams are moving to a school year age group model, this one slightly different to the one in England, quarters are defined as follows:

• Q1: Players born August 1 – October 31
• Q2: Players born November 1 – January 31
• Q3: Players born February 1 – April 30
• Q4: Players born May 1 – July 30

Splitting players into quarters will give you an insight on where they might be in their growth journey and inform your thinking about what you can expect from them as a player.

5. Split training groups accordingly

Running various stations of the same session? Asking players to compete 1v1 or 2v2? Think about how you’re grouping or splitting up your players so they have the best opportunities to learn and improve.

One way of grouping players is by physicality, to offer players an appropriate level of challenge.

6. Provide different opportunities
Coaches often talk about the concepts of being comfortable and being stretched or challenged. And both look different for different players. 

While players may be set to spend most of the season playing with their allocated team and age group, what different opportunities can you offer them to make sure they get appropriate levels of being comfortable and being stretched or challenged?

For a younger, less developed player, for example, this may mean playing down an age group at times, so they get to feel more in their comfort zone by playing against players of a similar stature and strength to them.

For an older, more developed player, this may mean playing up an age group at times, so they get challenged against stronger, faster players.

For some clubs, where resources and knowledge allow, this may bio-banding may be an answer. Bio-banding is the process of grouping young players by their biological and physical maturity level, rather than their chronological age, attempting to bridge speed and strength gaps created by different growth rates.

By estimating a player’s biological age by analysing their current height, weight, date of birth, and their parents’ heights to predict their percentage of adult height, coaches can estimate a player’s biological age, and then group them, for certain fixtures or events, accordingly.

This may allow players to play against physically similar peers. Later developers are therefore afforded a realm in which they can better explore their physicality, and earlier developers will be forced to work on their technical and decision-making abilities when they are better matched up physically.

6. Make informed decisions
If you’re the kind of team or club that has to make decisions, come the end of a season, about whether players are staying or being released, make these decisions with information about the relative age effect in mind, and with the future, rather than just the now, firmly in sight.

Being informed about RAE will support you as a coach and, as a result, your players.