Biermann Henrik, Memmert Daniel, Romeike Christian, Knäbel Peter, Furley Philip
German Sport University Cologne Cologne,Germany.
d-fine GmbH, Frankfurt, Germany.
J Sports Sci. 2024 Dec;42(24):2396-2401. doi: 10.1080/02640414.2024.2433895. Epub 2024 Nov 28.
The aim of this study was to investigate the well-known selection bias favouring players born earlier in the year commonly referred to as the Relative Age Effect (RAE). Therefore, we analysed a group of top-tier youth academy players. The players joined and left the youth academy at different stages, where the first stage was at 8 years (U9) and the last stage was at 18 years of age (U19). Subsequently, we followed the career paths of all players in terms of minutes played in professional competitions. For that purpose, we collected competition information from transfermarkt.de. We label a competition as professional if the included teams obtain an average market value of 100.000€ (aggregated value of players playing in the team) and recorded the professional career minutes (PCM) for all players. Results show that in the youth academy, there are fewer players that are born late in the year compared to players that are born early in the year, confirming previous findings of RAE. However, we also find that players that are born late in the year achieve more PCM on average. This indicates that players that survive the RAE selection bias are exceptionally good at achieving long, successful careers.
本研究的目的是调查一种众所周知的选择偏差，这种偏差有利于年初出生的球员，通常被称为相对年龄效应（RAE）。因此，我们分析了一组顶级青训营球员。这些球员在不同阶段加入和离开青训营，第一阶段是8岁（U9），最后阶段是18岁（U19）。随后，我们根据球员在职业比赛中的上场时间跟踪了所有球员的职业生涯路径。为此，我们从transfermarkt.de收集了比赛信息。如果参赛球队的平均市值达到100,000欧元（球队中球员的总价值），我们就将该比赛标记为职业比赛，并记录所有球员的职业生涯上场时间（PCM）。结果显示，在青训营中，与年初出生的球员相比，年末出生的球员较少，这证实了之前关于RAE的研究结果。然而，我们还发现，年末出生的球员平均获得的PCM更多。这表明，在RAE选择偏差中幸存下来的球员在取得漫长而成功的职业生涯方面格外出色。
