Relative age effects and the Premier League’s Elite Player Performance Plan (EPPP): A comparison of birthdate distributions within and between age groups

The purpose of this study was to investigate the prevalence of relative age effects (RAEs) within and between U18, U21 and professional senior squads, that compete in the highest (respective) leagues within England. Birthdate, playing position and age (years) of U18 (n = 487), U21 (n = 350), and senior (n = 396) players from squads competing in the highest divisions of their respective age groups were obtained. Moreover, nationality (UK or Non-UK) was recorded for U21 and senior players, with estimated market value also obtained for senior players. Chi-square tests, Cramer’s V and odds ratios with 95% confidence intervals were used to compare observed and expected birthdate distributions. A selection bias toward relatively older players was evident within U18 and U21 squads, across all positions. Furthermore, analysis of age bands within each age group also revealed an increase in the prevalence of RAEs throughout each age group. In contrast, analysis of senior squads revealed no significant deviations in birthdate distributions when considered as a whole sample, as separate age bands or by position. However, although non-significant, Q4 players were found to have the highest estimated market value. Results demonstrate RAEs are prevalent across U18 and U21 age groups at the highest level of competitive football within England, yet this is not representative of the birthdate distributions within senior squads. Ongoing research is needed to highlight the prevalence of RAEs within academies, particularly when these RAEs are not representative of birthdate distributions within professional senior squads.