It is better to be born in January to have a career in football

The tenth Monthly Report of the CIES Football Observatory analyses the relative age effect on the possibility to have a career in football. The study shows that players born in the first months of the year are strongly over-represented. It also highlights the existence of a selection bias favouring players with a precocious physical development.

Nowadays, throughout Europe, players with the disadvantages of being born in the last months of the year and of later physical development have little chance of pursuing a career at a high level. The authors recommend to organisations in charge of the development of youth players and the game to “take the question of the relative age effect seriously”.

According to the Report, the limiting of the selection bias linked to the date of birth and to the level of physical development would reinforce meritocracy in football. Over the long term, such a step forward would be beneficial not only to the level of spectacle that teams are able to provide, but also on the level of balance of competitions.

English players are the only ones born on average after July 1st, the average date of birth of a typical citizen. This can be explained by the fact that age classes in English football are based on the cut-off date used by the school system, the 1st September, and not the 1st January as in other countries. Consequently, the least represented players among English professional footballers are those born in August and not in December as in the 30 other associations surveyed.

Issue number 128 of the Big-5 Weekly Post presents the data on the average day of birth of players for each club of the five major European leagues. In 23 teams only, this date is after July 1st. The extreme values were recorded at Fiorentina (20 April) and Southampton (11 August).