The influence of age-policy changes on the relative age effect across the Australian Rules football talent pathway

Abstract

Objectives: To identify the influence of age-policy changes on the relative age effect (RAE) across the Australian Football League (AFL) talent pathway.

Design: Retrospective cross-sectional analysis of junior AFL players attending the National Draft (National), State, and State Under 16s (U16) combines between 1999–2016.

Methods: Birth-date data was obtained for players attending the AFL State U16 (n = 663, age: 15.9 ± 0.4 years), State (n = 803, age: 19.1 ± 1.7 years), National (n = 1111, age: 18.3 ± 0.8 years) combines. Corresponding aged-matched Australian general population birth rate data was also collected.

Results: A chi-squared analysis comparing birth month distributions found all combine groups differed significantly from the general population (Under 16s: χ2 = 62.61, State: χ2 = 38.83, National: χ2 = 129.13, p < 0.001). Specifically, Under 16s had greater birth frequencies for months January to March (≥2%, p < 0.05), with more State players born in January (4.9%, p < 0.05). Age-policy changes at the National level reduced birth distribution bias for some months, however the RAE remained for March, June and July (3.9%, 6.1%, 4.3%, p < 0.05). State U16s and National players had 2–9% lower birth frequencies for November–December births compared general population.

Conclusions: Selection bias exists towards older players is present at the AFL’s State U16, and is maintained at State and National level combines. Age-policy changes are only partially successful at addressing the RAE at the National level, with alternative strategies also recommended in order to address the RAE across the AFL talent pathways.