Several mechanisms potentially contribute to relative age effects, including sport structure, physical, and social mechanisms. A brief description of each is provided.
Sport Structure Mechanisms
To maintain fair athletic competition, organizations often institute one- or two-year age bands (e.g., players born in 2008 and 2009 compete in U8 soccer). Even in a one-year age band, athletes’ ages can differ by 364 days. While smaller age bands and rotating cut-off dates have been proposed, these solutions provide many administrative challenges. Thus, the inherent sport structure lends itself to relative age effects.
Physical Mechanisms
Though not guaranteed, being chronologically older than one’s peers can lead to growth and maturation advantages. The average child who is 8 years and zero days old (e.g., born January 1) weighs 58lbs and stands 51” tall; meanwhile the average child who is 7 years and one day old (e.g., born December 31) weighs 51lbs and stands 48” tall. Both children play in the same age division, but the older child has a distinct physical advantage. Additionally, maturation advantages (e.g., better coordination, advanced cognitive efficiency) often exist for relatively older children.
Social Mechanisms
Parents appear to register their relatively older children in sport at younger ages. This initial experience results in more practice, competition, and instruction. It has been proposed that such initial advantages lead to later advantages (i.e., a Matthew Effect), including selection to elite teams. Further, it is suggested that parents and coaches place higher expectations on relatively older players, also leading to increased practice, competition, and instruction. These expectations (i.e., a Pygmalion Effect) are then met by players, who show advanced skill development
