GLOBAL ANALYSIS OF 55,000+ FIFA PLAYERS

Hero Sports Data has analysed more than 55,000 FIFA professional player records to better understand the Relative Age Effect in football — the tendency for players born earlier in the football year to be overrepresented in elite and professional pathways.

The findings are clear: this is not a small or isolated issue. Across countries, leagues, positions and player ratings, the data suggests football systems may be unintentionally favouring players born earlier in the selection year.

Key findings

Across our global FIFA player dataset:

  • 33.8% of players were born in Quarter 1 of the football year
  • A neutral distribution would be 25%
  • Quarter 4 players made up only 17.6% of players
  • In a sample of more than 55,000 players, Quarter 1 players are overrepresented by more than 4,000 players

Players born early in the selection year appear much more frequently in professional football than those born at the end of the year.

This suggests a significant cohort of potential players may be missing from the professional football pathway.

Consistent trend worldwide

One of the clearest findings in our research is how consistent the Relative Age Effect appears across major football countries.

We analysed player birth-quarter data from leading nations including England, Spain, Argentina and France. Despite differences in football culture, league structures and player pathways, the same overall pattern emerges in every case: players born early in the football year are significantly overrepresented, while players born later in the year are underrepresented.

The similarity is striking. In all four countries, Quarter 1 players make up around one-third of professional players, while Quarter 4 players sit closer to 15–17%.

This suggests the Relative Age Effect is not a country-specific issue. It is a broader structural outcome of age-group football, where early physical maturity can create advantages in selection and development.

See below for an analysis of some countries with lower RAE impacts and relative outperformance.

Australia shows the same trend

The Australian data follows the same broad trend.

Among Australian FIFA-listed players, Quarter 4 players make up only 19.6% of the sample, compared with an expected 25%.

Because Australian youth football generally runs on a January to December age-year structure, this means players born later in the calendar year may face the same structural disadvantage seen globally.

The important point is that when the age-group calendar changes, the pattern moves with it.

That suggests the issue is not random. It is linked to the way football organises youth development.

The system doesn’t intentionally favour older kids — but the structure can create that effect.

A League players show the same trend, with an even higher proportion of Q1 players than Australians playing globally.  32.2% are born in Q1.

Many Relative Age Effect charts assume births are evenly spread across the year. But in Australia, they are not. More children are naturally born in Q3 and Q4 than Q1. That means when football pathways still over-select Q1 players, the true bias is even stronger than raw player percentages suggest.

RAE - a well known phenomenon

What is the Relative Age Effect?

The Relative Age Effect occurs when players born earlier in a selection year are more likely to be selected, developed and retained than players born later in the same selection year.

In youth football, age groups are usually organised by fixed cut-off dates. Depending on the country or competition, the football year may run from January to December, September to August, or another defined period.

This means two players in the same age group can be almost twelve months apart in actual age.

At age 10, that can mean huge differences in strength, speed and coordination.

The older player may be:

  • taller
  • stronger
  • faster
  • more coordinated
  • more confident
  • more physically ready for competition

Coaches may not be intentionally biased. But when physical maturity looks like football ability, older players can be selected more often.

Over time, this can become a compounding advantage. The cumulative advantage may lead to a professional population skewed toward players born early in the selection year.

Football academies are designed to find talent — but they may also be accidentally filtering it.

Implications: missing a whole funnel of players

The System Loses Talent EARLY — Not LATE. The biggest loss of talent happens at ages 8–14, not at elite level.

Once the older players are selected into stronger teams or development programs, they often receive:

  • better coaching
  • more training intensity
  • more minutes
  • stronger competition
  • more confidence

This has implications for the total player funnel. Players born late in the selection year may be smaller or less physically developed at the exact time when early pathway decisions are made. Some may be overlooked, receive fewer opportunities or leave the system before their long-term potential becomes visible.

Relative Age Effect may mean:

1. Reduced talent pool - potential elite players lost early.

2. Narrower funnel - selection based on maturity rather than long-term upside.

3. Less diversity of player types - especially smaller technical players.

4. Lower long-term national ceiling - best available talent may not fully reach the system.

This is the hidden risk. Football may not only be selecting talent. It may also be filtering players before their talent has had time to emerge.

Does it affect all positions?

Yes. The effect appears across positions, but it is not equally strong everywhere.

In our analysis, defenders showed the strongest effect, with approximately 35% born in Quarter 1.

This makes intuitive sense. Defensive positions often reward:

  • height
  • strength
  • physical presence
  • aerial ability
  • early competitiveness in duels

In youth football, those traits may be closely linked to relative age and maturity.

The implication is that some positions may be more vulnerable to early physical selection bias than others. Technical positions may show weaker effects because skill, agility and decision-making can sometimes compensate for size. 

However, the broader RAE pattern remains visible across the game.

Leagues - Serie A: strongest example

The Relative Age Effect is visible globally, but the strength of the effect differs by league. That variation matters.

If some leagues show a stronger skew and others show a weaker skew, then RAE is not inevitable. It may be influenced by how football systems identify, select, retain and develop players.

Serie A: a striking example

One of the strongest examples in our analysis is Serie A, where 50.4% of players were born in Quarter 1.

This figure should be interpreted carefully. Not all players in Serie A are Italian, so the finding should not be treated as a pure measure of Italian youth development. However, it is still an important data point. It raises questions about whether some high-level football environments may favour players who were physically ready earlier in the pathway.

At a time when Italian football has faced broader debate about youth development, senior national team performance and transition opportunities for young players, the Serie A result is worth further exploration.

The question is not whether physical attributes matter. They clearly do in football. The question is whether they are overweighted too early relative to long-term football potential.

FIFA rating analysis

The data also raises an interesting question: are early-born players actually better, or are they simply more likely to be selected?

Our analysis of FIFA ratings suggests that Quarter 4 players who reach the professional level may perform strongly relative to their representation.

The top 20% of FIFA-rated players have a higher percentage of Quarter 4 players than the bottom 20%:

  • Top 20%: 18.0% Quarter 4
  • Bottom 20%: 16.8% Quarter 4

This may point to a survivor effect. Late-born players often face more friction in the development pathway. They may receive fewer early opportunities, be physically smaller, or have to prove themselves for longer.

Late-born players often start with disadvantages. They may be smaller. They may get fewer opportunities.

“But the ones who persist often develop resilience. By the time physical differences disappear, they can be extremely strong competitors.”“Sometimes  the players who beat the system become the best players in it.

The average FIFA rating of Q4 players is the highest.  In simple terms this is a clear indication that the overall quality of profssional football would be higher if there was equal representation across all quarters.

Insights from England and the Premier League

The Premier League, widely regarded as the strongest league in the world, has a lower Relative Age Effect than England players overall.

Although international players influence the full league numbers, the same pattern appears when looking only at English Premier League players. They have a lower Q1 share and a much higher Q4 share than the wider England group. 21.9% of english players in the Premier League are born in Q4 compared to only 16.1% of all England professional players.

This suggests that the broader English pathway may be developing or selecting too many Quarter 1 players relative to Quarter 4 players.

In other words:

  • the domestic system may be over-rewarding early-born players
  • but the very top level appears to contain a somewhat more balanced group
  • later-born English players who reach the Premier League may be stronger than their wider representation suggests

Countries that outperform with lower Q1 bias

Football development systems vary dramatically across countries. Using nationality data, we can compare how different football cultures shape professional players.

Some countries show stronger birth-quarter bias than others.

This may reflect differences in academy systems, scouting structures and grassroots participation.

Our analysis also considered countries that are often viewed as football overperformers relative to population size and resources. Countries such as:

  • South Korea
  • Croatia
  • Colombia
  • Japan
  • Portugal

appear to show a lower Quarter 1 effect in the dataset.

This is important because smaller countries cannot afford to waste talent. A broader development funnel may help retain more late developers, smaller technical players and players who do not dominate physically at young ages.

This does not prove a single cause of success. But it does raise an important question: Do some football systems outperform because they lose fewer players too early?

Countries taking action

If football wants to find the best players, it needs to widen the pathway. Many federations are now trying to reduce the relative age effect.

Some systems use bio-banding, grouping players by biological maturity rather than age.

Others run parallel development squads to track late developers.

These strategies aim to ensure that smaller or later-developing players aren’t excluded too early.

What are other countries doing?

Belgium - Belgium has used approaches such as bio-banding and broader development tracking to reduce the risk of losing late developers.

Scotland - Scotland has explored development squads and wider monitoring pools to track players who may not be physically ready early but still have long-term potential.

England - Some English academies have trialled bio-banded competitions, where players are grouped by biological maturity rather than chronological age.

The goal isn’t just fairness — it’s making sure the game doesn’t miss future stars. Because some of the best players in football history nearly slipped through the system.

Additional work planned

Hero Sports Data is continuing to expand this work. Further analysis being prepared includes:

  • National team analysis (World Cup and Euro teams)
  • NPL NSW and VIC Men’s First Grade analysis using public data
  • Female player analysis
  • Individual team analysis
  • Further work on player rating, position and birth-quarter relationships

What could football do differently

Measure the issue

Track birth-quarter distribution across age groups, clubs, leagues, positions and selection levels.

Educate coaches

Help coaches distinguish between physical maturity and long-term potential.

Widen the funnel

Avoid early deselection where possible and create re-entry points for late developers.

Consider bio-banding pilots

Group players by biological maturity in selected training or competition settings.

Track late developers

Create parallel monitoring systems for players who are technically strong but physically behind.

Review position-specific bias

Pay particular attention to roles where size and physicality are heavily rewarded early, such as defenders and goalkeepers.

CLOSING MESSAGE

If football wants the best players, it must make sure it is not losing them at age 9.

Relative Age Effect is measurable.

It is understandable.

And with the right approach, it can be managed.

The opportunity is clear: widen the funnel, keep more players visible for longer, and give football a better chance of finding the talent it may currently be missing.