[1][2] On 11 September 2020, the CIES released their annual rankings of the clubs having trained the most players active in 31 top divisions of UEFA member associations.

In accordance with the UEFA definition, players who were considered have been playing for the club for at least three seasons between 15 and 21 years of age.

[3] The Ajax youth system is famous for having produced and still producing many great Dutch internationals like Sjaak Swart, Johan Cruijff, Frank Rijkaard, Dennis Bergkamp, Frank and Ronald de Boer, Edgar Davids, Clarence Seedorf, Patrick Kluivert, Rafael van der Vaart, Wesley Sneijder, John Heitinga, Nigel de Jong, Maarten Stekelenburg, and Gregory van der Wiel.

Ajax has developed the so-called TIPS model, which stands for Technique, Insight, Personality and Speed.

[11] Here the players are trained in a scientific manner based on motion analytics to enhance speed, distance, dribbling, heading and shooting.