Relative age effects in female sport contexts: A systematic review and meta-analysis of data (1984-2016)

Subtle age differences can lead to immediate participation and long-term attainment influences in sport; commonly known as Relative Age Effects (RAEs; Barnsley et al., 1985). The prevalence of the RAE remains relatively undetermined for female sport contexts. Accordingly, the objective of this study was to examine female participation trends with respect to relative age in the published literature by evaluating the birth quartile distribution of athlete samples. Following PROSPERO (Reg. no. 42016053497) and PRISMA systematic search guidelines, 57 studies spanning 1984–2016 were identified and contained 308 independent samples across 25 sports. The overall prevalence and strength of the RAE across and within female sports contexts was determined, and moderator variables were assessed using odds ratio (OR; events vs. non-events) meta-analyses, applying an invariance random-effects model. The overall pooled estimate comparing the relatively oldest (Q1) v relatively youngest (Q4) suggested a small, but significant RAE (OR 1.25; 95% CI = 1.21-1.30; p = 0.01). Sub-group analyses revealed RAE magnitude was greater at pre-adolescent and adolescent age groups (