Does the Relative Age Effect Exist in Elite Sport? An Analysis of Olympic Competition

Studies have concluded that youth sports programs have a bias selection process in identifying player talent. Athletes that are identified as talented are more likely to be born in the first three months after the eligibility cut-off for a program's particular age group. This is referred to as the relative age effect (RAE) and has been identified in many youth sports. However, it is not known if the RAE carries over into elite, adult competition. The purpose of this study was to determine if the RAE exists in Olympic competition and to compare the RAE between genders, team vs individual sports, weight class vs non-weight class sports, and medalists vs non-medalists. Data on Olympians competing in the 2012 London and 2016 Rio de Janeiro Olympics were gathered from publicly available databases. Lorenz curves were constructed and Gini coefficients calculated to detect unexpected distributions of birth months. In addition, linear regression was used to determine a directional distribution. A negative Gini coefficient and a statistically significant negative slope of the birth month distribution suggested the existence of a RAE. The results showed that there was a RAE in Olympic competition. For all athletes, the Gini coefficient was -0.0324 and the slope of -0.0014 fraction of athletes born per month. Within specific sports, the RAE varies considerably with some showing a positive RAE. Further, the RAE in Olympic athletes does not seem to be influenced by gender, type of team or success of the athlete.