The relative age effect in Europe's "Big 5" women's leagues

Regular visitors to the FIFA Training Centre will be familiar with the relative age effect (RAE), a form of bias that systematically advantages players born early in the calendar year. While several previous presentations have explored this key issue in the context of the men’s game, this one turns our attention to women’s football and explains how the RAE is influencing every level of the development pyramid – up to and including Europe’s top senior leagues.

• The relative age effect exists across all five of the “Big 5” European women’s leagues. This has the potential to limit opportunities for female players born later in their birth year. 

• One potential contributor to the emergence of the relative age effect could be the recent boom in female participation in football. This development may also be linked to the rapid professionalisation of the women’s game.

• There are a number of measures practitioners could implement to counter the effects of the RAE and ensure all young female players get the chance to shine.

Part 1: The RAE and its impact on football
The relative age effect (RAE) is a bias in talent development that favours players born in the first half of the calendar year. These players tend to be over-represented in youth teams because they are usually more physically mature than other players in their age group. This bias persists as players move through the youth pyramid and into the senior game. Previous research has suggested the strength of the RAE varies between positions, with goalkeepers and defenders being more affected than other players.

Part 2: The study and its main findings
This study examined how the RAE affects Europe’s “Big 5” senior women’s leagues (in England, France, Germany, Italy and Spain). The authors analysed a data set of over 1,600 players, and found evidence that the RAE was evident across the five leagues as a whole, as well as within each of these competitions individually. However, there were some striking differences between countries: the German Frauen-Bundesliga was the only league in which the RAE affected forwards, while the English Women’s Super League was the only one in which the RAE was seen in defenders.

Part 3: Discussion and implications
The number of women playing football has rocketed in recent years, and this growth has been accompanied by a rapid professionalisation of the women’s game. These changes have in turn prompted an increased emphasis on performance, and this may be one reason (among many others influencing both men’s and women’s football) for the emergence of the RAE as a factor at women’s youth World Cups. The increasing prominence of the RAE throughout the pyramid underlines the need to ensure that later-developers get the chance to showcase their talent, and practitioners could consider measures like bio-banding to make sure they get their opportunity to shine.

Paper citation
Pérez-González B, Iván-Baragaño I, Bonal J, León-Quismondo, J, Fernández-Luna, Á & Burillo P. (2025). Born to Win? Investigating the relative age effects in the big five European women’s football leagues. Frontiers in Sports and Active Living, 1546913.

You can read the full article here.