The relative age effect in European Professional Soccer: Is there any difference after ten years of research?

Abstract

The relative age effect (RAE) refers to an asymmetry in birth-date distribution favoring players born early in the selection year and discriminating participants born later in the year. While the RAE effect was initially reported in sport more than two decades ago, there have been few attempts to examine whether player selection strategies have changed over time in light of our improved understanding of the phenomenon. In a first study, we compared the birth-date distributions of professional soccer players in ten European countries over a 10-year period involving the 2000-2001 and 2010-2011 competitive seasons, respectively. Chi-square goodness-of-fit tests were used to compare differences between the observed and expected birth-date distributions across selection years. Generally, results indicated no change in the RAE over the past 10 years in professional soccer emphasizing the robust nature of this phenomenon.  In a second study, the impact of the RAE is examined for players progressing from youth squads to the professional teams. We analyzed the birth-date distributions of 17-23 years old players in 7 European countries over a 3-years period involving the 2010-2011, 2011-2012 and 2012-2013 competitive seasons. Results showed a significant overrepresentation of players born in the first quarter (37.3%) of the selection year compared to the last quarter (13.9%). Players with a greater relative age are more likely to progress from the youth categories to the professional teams. Social agents that impact on RAEs are discussed as well as structural solutions to reduce the impact of the RAE on talent identification and selection.