Relative age effect reversal on the junior-to-senior transition in world-class athletics

11,629 athletes

World-ranked athletics athletes: 5,766 sprinters (51.0% female) and 5,863 jumpers (45.9% female)

Large registry cohort of world-ranked sprinters and jumpers, tracking birth-quartile distribution at U18 vs senior and modelling odds of transitioning to senior top level. Objective administrative data (birth dates, official rankings), no self-report. Observational: cannot separate 'underdog' compensation from regression of the maturity advantage plus differential attrition of early-maturing Q1 athletes.

Direct demonstration that RAE is a junior selection artifact that vanishes — and reverses in transition odds — by senior world class. The relatively youngest juniors who survive selection are MORE likely to become senior top performers (OR ~1.64). Practically: junior rosters are contaminated by birth-date/maturity noise, and a competitive Q4 junior is a stronger talent signal than an equally-ranked Q1 junior. Fits the broader finding that junior performance poorly predicts senior world-class status.

U18 selection partly indexes heritable maturational timing rather than heritable performance capacity; the reversal is consistent with underlying capacity reasserting itself once maturity differences equalize.

Consistent with NHL 'underdog'/RAE-reversal findings (PLOS ONE 2017) and rugby union senior-transition data; magnitude varies by sport and some studies find only attenuation, not reversal.