Authors: Benito Pérez González et al.
Journal: Frontiers in Sports and Active Living, 2025

AI written summary:

Aim

The study examined whether Relative Age Effects (RAEs) — the advantages experienced by players born earlier in the selection year — exist in the top five European women’s football leagues (England, Spain, Germany, Italy, France) during the 2023/24 season. It also explored whether RAEs differ by playing position.

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Methods

• Sample: 1,634 professional players from the Women’s Super League, Liga F, Frauen-Bundesliga, Serie A Femminile, and Division 1 Féminine.
• Data: Players’ birth dates, positions (goalkeeper, defender, midfielder, forward), and clubs.
• Analysis: Chi-square and Poisson regression to test for uneven birth-date distribution across quartiles and leagues.
• Index of Discrimination (ID): Measured how much more likely early-born players were to appear in elite squads.

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Results

• Overall RAE confirmed: Players born early in the year were 1.57 × more likely to be represented than those born later (p < 0.001).
• By league:
  • Significant RAEs in England, Spain, Italy, and France.
  • No significant RAEs in Germany (Frauen-Bundesliga).
• By position:
  • Significant RAEs among goalkeepers (ID = 2.11) and midfielders (ID = 1.72).
  • No significant RAEs for defenders or forwards.
• Quartile trend: 56 % of all players were born in the first half of the selection year (Q1 + Q2).

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Discussion

• The persistence of RAEs in most leagues mirrors findings in men’s football and other sports.
• The absence in Germany may relate to differences in youth systems, participation rates, or selection intensity.
• Positional effects suggest that goalkeepers and midfielders, often chosen for tactical or physical maturity reasons, may be more influenced by age-related selection bias.
• Increasing professionalization and competitiveness in women’s football likely amplifies RAEs, as selection pressure grows with larger player pools.
• Mitigating strategies such as bio-banding, adjusted scouting criteria, or awareness training for coaches could promote fairer talent development.

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Limitations

• Cross-sectional (one season only).
• Focused solely on top divisions; youth and lower tiers not analyzed.
• Did not account for cultural or developmental system differences between countries.

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Practical implications & future research

• Clubs and federations should monitor RAE patterns to avoid losing late-born talent.
• Further longitudinal and multi-level studies are recommended to track changes over time and test interventions.
• Exploring social and maturational factors (e.g., motivation, support, physical development) may explain why RAEs differ by gender or country.

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Key takeaway

Relative Age Effects remain prevalent in elite European women’s football — especially in England, Spain, Italy, and France — and are most pronounced among goalkeepers and midfielders.
Addressing these biases is vital to ensure fair, evidence-based talent identification and long-term player development.