Relative Age Effect in football

Relative age effect refers to the overall difference between players in the same age group. Players born in the first months of a year are physically more developed than players born in the last months of the same year. Most of the time, players born in January will be stronger than players born in the same year in December. You don’t need to be a scientist to figure that out. Certainly at a young age the difference can be huge. For players around the age of 12, eleven months of difference can be crucial.

We already discussed this issue a lot the last couple of years in sports magazines, books, conferences… The Belgian Football Federation also discussed this matter frequently with their coaches, staff and instructors. Until now we did not really find a solution to prevent this from happening. We have had a Shadow U15 Team, Late U15 Team, Early U15 Team and a Normal U15 Team. It was a good initiative but this was maybe a bit too much and they screwed it back to a Normal U15 Team and a Future U15 team. I think this is probably the most you can do as a Federation. You don’t have a lot of time with the players, so working with 2 groups should be enough. For me personally the main issue is that the Belgium Football Federation were the only ones that followed this up though. I think this all needs to start at a younger age and in all the domestic clubs, no matter if it is Elite football or Amateur football.

Making youth players better is much more important than winning games

Don’t get me wrong and I will not be hypocrite about this either. At the end, in sports, it is about winning at an Elite level. Though, I am convinced that making players better will make you win more trophies at the end too. All of our youth academies should take their responsibility and try to reduce this effect. Too often we see clubs at the end of the season bringing on more physically strong players to win their games and eventually the competition. We don’t always give the technical gifted players a chance to compete in the most important games of the season/tournament. It are those games that are so important for their development.

The main problem is that the players who are more mature and stronger will have played more games. They play more minutes during competitions and are selected faster for their national team, which gives them an advantage over less mature players. Sometimes there are extra training sessions for a happy few, the so called best players of the group. This all makes them gain more self-confidence, gets them train with better coaches, be more efficient…

The most important thing for me is to get rid of the short-term approach in youth football. Until the age of 16 we need to reduce the relative age effect. Talent identification should be more aware of the fact that, in the same age group, their can be a big physical difference between players. Big selections or talent detection should not be made at too young an age. Monitoring the maturation of young talented players can help a lot to reduce this effect. We need to focus on the whole package.

Bassevelde U13 Cup

Like every year I went to the prestigous international tournament in Bassevelde this year. 16 clubs competed for the so called “Champions League” for U13 teams. I did a little research with all the data I could find. More than 90% of the players are included in this small research.

I’ve gathered data of 325 players who played at the Bassevelde U13 Cup in 2017:

Out a total of 325 players, 195 of them are born between January and July

Out a total of 325 players, 195 of them are born between January and July

  • 16 teams were present this season at the tournament
  • The final was played between Celtic and Anderlecht. Out of the 18 players of Celtic only 2 of them were born in July or later. Anderlecht had 6 players born in July or later out of a total of 18 players.
  • The only team who had more players born in the last 6 months was Next Gen USA. They’ve had 9 players born in July or later out of 16. They finished the tournament as number 12.
  • 60% of the players at the Bassevelde U13 Cup were born in the first six months of the year.
  • The winner of the Bassevelde U13 Cup has more than 88% of their players born in July or later!

Amount of players born in each month:

Although this is a small sample we can spot the difference in this U13 age group

Although this is a small sample we can spot the difference in this U13 age group

This doesn’t say everything, I know. The sample isn’t big enough to prove this on a bigger scale. Though, it is another example and prove that the relative age effect is a thing in football and sports in general. The more we will discuss about it the closer we will come to a solution.

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  1. Philip

    Hi Bjorn, thanks for the interesting article. I’ve read something similar about English football, but because of the way school years and football seasons are organised that article claimed the advantage lay with those born September to February. Any thoughts on the difference?

  2. Steve Jones

    In England we go by school years September to August, so this is even more apparent when an English team plays a Scottish or Irish team in the same age group as they use January to December and are listed as the same age. It clearly does have an effect.

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