  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.
