Relative Age Effect in Elite Sports: Methodological Bias or Real Discrimination?

TL;DR

This study questions whether the observed relative age effect in elite sports is a genuine discrimination or a result of methodological bias, based on analysis of a large sample of French male soccer players.

Contribution

It highlights potential biases in statistical testing of the relative age effect, challenging previous conclusions about systemic discrimination in athlete selection.

Findings

Potential bias in statistical tests of the relative age effect

Questioning the validity of previous claims of discrimination

Implications for future research methodology in sports science

Abstract

Sport sciences researchers talk about a relative age effect when they observe a biased distribution of elite athletes' birthdates, with an over-representation of those born at the beginning of the competitive year and an under-representation of those born at the end. Using the whole sample of the French male licensed soccer players (n = 1,831,524), our study suggests that there could be an important bias in the statistical test of this effect. This bias could in turn lead to falsely conclude to a systemic discrimination in the recruitment of professional players. Our findings question the accuracy of past results concerning the existence of this effect at the elite level.