Background: In football, annual age-group categorization leads to relative age effects (RAEs) in talent development. Given such trends, relative age may also associate with market values. This study analyzed the relationship between RAEs and market values of youth players. Methods: Age category, birthdate, and market values of 11,738 youth male football players were obtained from the “transfermarkt.de” database, which delivers a good proxy for real market values. RAEs were calculated using odds ratios (OR) with 95% confidence intervals (95%CI). Results: Significant RAEs were found across all age-groups (p < 0.05). The largest RAEs occurred in U18 players (Q1 [relatively older] v Q4 [relatively younger] OR = 3.1) ORs decreased with age category, i.e., U19 (2.7), U20 (2.6), U21 (2.4), U22 (2.2), and U23 (1.8). At U19s, Q1 players were associated with significantly higher market values than Q4 players. However, by U21, U22, and U23 RAEs were inversed, with correspondingly higher market values for Q4 players apparent. While large typical RAEs for all playing positions was observed in younger age categories (U18–U20), inversed RAEs were only evident for defenders (small-medium) and for strikers (medium-large) in U21–U23 (not goalkeepers and midfielders). Conclusions: Assuming an equal distribution of football talent exists across annual cohorts, results indicate the selection and market value of young professional players is dynamic. Findings suggest a potential biased selection, and undervaluing of Q4 players in younger age groups, as their representation and market value increased over time. By contrast, the changing representations and market values of Q1 players suggest initial overvaluing in performance and monetary terms. Therefore, this inefficient talent selection and the accompanying waste of money should be improved.

中文翻译：

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相对年龄效应如何与足球运动员的市场价值相关联：人才流失和浪费金钱的指标

背景：在足球领域，每年的年龄组分类会导致人才发展中的相对年龄效应 (RAE)。鉴于这种趋势，相对年龄也可能与市场价值相关联。本研究分析了 RAE 与青年球员市场价值之间的关系。方法：从“transfermarkt.de”数据库中获取了 11,738 名青年男子足球运动员的年龄类别、出生日期和市场价值，该数据库很好地代表了真实市场价值。RAE 使用比值比 (OR) 和 95% 置信区间 (95%CI) 计算。结果：在所有年龄组中都发现了显着的 RAE ( p< 0.05)。最大的 RAE 发生在 U18 球员中（Q1 [相对年龄较大] v Q4 [相对较年轻] OR = 3.1） OR 随年龄类别而下降，即 U19 (2.7)、U20 (2.6)、U21 (2.4)、U22 (2.2)和 U23 (1.8)。在 U19 中，Q1 球员的市场价值明显高于 Q4 球员。然而，到了 U21、U22 和 U23，RAE 出现了反转，第四季度参与者的市场价值相应更高。虽然在较年轻的年龄组（U18-U20）中观察到所有比赛位置的大型典型 RAE，但只有 U21-U23 的后卫（小中型）和前锋（中型）（不是守门员和中场）的反向 RAE 很明显. 结论：假设足球人才在年度队列中存在平均分布，结果表明年轻职业球员的选择和市场价值是动态的。调查结果表明，由于他们的代表性和市场价值随着时间的推移而增加，因此存在潜在的偏见选择，并低估了年轻年龄组的第四季度球员的价值。相比之下，第一季度参与者不断变化的表现和市场价值表明，最初的业绩和货币价值被高估了。因此，这种低效的人才选择和随之而来的金钱浪费应该得到改善。