Relative Age Effect: Beyond the Youth Phenomenon.

Introduction. The relative age effect (RAE) refers to performance advantage of youth born in the first quarter of the birth year when auditioning for select, age-restricted sports. This advantage conferred to the older athlete is a result of being more physically and emotionally mature, therefore, assumed to be a more advanced player. We hypothesize an RAE exists in Olympic athletes, and this extends across selected categories of athletes (by gender), such as team versus individual sports, winter versus summer athletes, and sports using a ball versus those not using a ball. Methods. We extended the exploration of an RAE beyond specific sports by examining the birth quarter of more than 44 000 Olympic athlete's birthdates, born between 1964-1996. The data were summarized by birth quarter (January 1 to March 31, etc) and presented as percentages and 95% confidence intervals. Results. The fractions of births in the first versus the fourth quarter were significantly different ( P < .001) from each other for the summer and winter Olympians, ball and nonball sports, and team as well as individual sports. Conclusions. The general presence of an RAE in Olympic athletes exists regardless of global classification.