My Research: Relative Age Effect

I have looked into months of birth of all under-23 players who have appeared in Europe’s top five leagues and the group stages of Champions, Europa and Nations Leagues so far this season.

CONCLUSIONS:

• Under-23 players born in the first quarter of a year dominate in every single competition analysed, with players born in the second quarter of a year always directly behind or, in only one instance, level.
• Under-23s born in the last quarter of a year come bottom in most competitions analysed.

NOTE:

For players having come through the English system I treated September as the first month of a year, October as the second and so on.

PREMIER LEAGUE:

Out of 66 under-23 players to have made at least one Premier League appearance so far this season:

• 24 (36.4%) were born in the first quarter of a year,
• 22 (33.3%) were born in the second quarter of a year,
• 12 (18.2%) were born in the third quarter of a year,
• 8 (12.1%) were born in the fourth quarter of a year.

Among under-23s who have come through the English system not a single one was born in August, i.e. the last month of the year. Southampton’s Michael Obafemi and Nathan Tella are the only two to have been born in July, i.e. the penultimate month of the year. Leicester’s Luke Thomas, Everton’s Tom Davies and Crystal Palace’s Eberechi Eze are the only three to have been born in June.

LA LIGA:

Out of 85 under-23 players to have made at least one La Liga appearance so far this season:

• 36 (42.4%) were born in the first quarter of a year,
• 22 (25.9%) were born in the second quarter of a year,
• 12 (14.1%) were born in the third quarter of a year,
• 15 (17.6%) were born in the fourth quarter of a year.

BUNDESLIGA:

Out of 93 under-23 players to have made at least one Bundesliga appearance so far this season:

• 30 (32.3%) were born in the first quarter of a year,
• 29 (31.2%) were born in the second quarter of a year,
• 21 (22.6%) were born in the third quarter of a year,
• 13 (14%) were born in the fourth quarter of a year.

SERIE A:

Out of 94 under-23 players to have made at least one Serie A appearance so far this season:

• 42 (44.7%) were born in the first quarter of a year,
• 22 (23.4%) were born in the second quarter of a year,
• 14 (14.9%) were born in the third quarter of a year,
• 16 (17%) were born in the fourth quarter of a year.

LIGUE 1:

Out of 155 under-23 players to have made at least one Ligue 1 appearance so far this season:

• 55 (35.5%) were born in the first quarter of a year,
• 43 (27.7%) were born in the second quarter of a year,
• 31 (20%) were born in the third quarter of a year,
• 26 (16.8%) were born in the fourth quarter of a year.

TOP FIVE LEAGUES:

Out of 487 under-23 players to have made at least one appearance in one of Europe’s top five leagues so far this season:

• 185 (38%) were born in the first quarter of a year,
• 136 (27.9%) were born in the second quarter of a year,
• 89 (18.3%) were born in the third quarter of a year,
• 77 (15.8%) were born in the fourth quarter of a year.

CHAMPIONS LEAGUE:

Out of 130 under-23 players to have made at least one Champions League appearance so far this season:

• 46 (35.4%) were born in the first quarter of a year,
• 36 (27.7%) were born in the second quarter of a year,
• 23 (17.7%) were born in the third quarter of a year,
• 25 (19.2%) were born in the fourth quarter of a year.

EUROPA LEAGUE:

Out of 232 under-23 players to have made at least one Europa League appearance so far this season:

• 75 (32.3%) were born in the first quarter of a year,
• 67 (28.9%) were born in the second quarter of a year,
• 50 (21.6%) were born in the third quarter of a year,
• 40 (17.2%) were born in the fourth quarter of a year.

NATIONS LEAGUE:

Out of 63 under-23 players to have made at least one Nations League appearance for one of 24 Euro 2020 participants so far this season:

• 19 (30.2%) were born in the first quarter of a year,
• 19 (30.2%) were born in the second quarter of a year,
• 13 (20.6%) were born in the third quarter of a year,
• 12 (19%) were born in the fourth quarter of a year.

All data is up to date as of 13 November 2020.

In the picture: Leicester City’s Wesley Fofana is currently one of just two Premier League under-23 players who have been born in the last month of a year (credit: Getty Images)