A Study of Relative Age Effect in Professional Leagues (The Sample of Turkish Super League, 1st League, 2nd League and 3rd League)

This present study aims to examine the phenomenon of the relative age effect among football players based on birth year and the positions they played in Turkish professional leagues. A total of 3622 professional football players from Turkish Super League, Spor Toto 1stLeague, 2ndLeague and 3rd League were included in the study. The players were divided into 4 different quarters with 3-month intervals and 2 different half-terms with 6-month intervals starting from January. The data of the second half of the 2021-2022 football season were used in the research. The data of the study were obtained from the official and open-access web pages of the Turkish Football Federation and Transfermarkt. With the chi-square test, the distribution of the football players according to birth months, positions and leagues and the frequency distribution differences between the groups were analyzed. SPSS 22 statistical package program was used to analyze data and the significance level was accepted as p<0.05. As a result, it has been observed that the number of football players born in the first quarter and the first 6 months of the year in all of the professional leagues in Turkey is more than the players born in the other quarters of the year, and the results were found statistically significant. In addition, it has been determined that there are more football players born in the first months of the year in all positions according to the leagues. As a result, the presence of relative age effect in football players playing in professional leagues in Turkey has been revealed.