8 June 2010. The study has examined the make-up of all national teams and their respective performance at the Football World Cup in Germany four years ago. It was conducted on the basis of the detailed career profiles of the 736 players and the results of the 64 matches, with the following results:

1. It has a positive impact on the results of a national football team if its ranks contain as high as possible a number of players who have played for foreign clubs for as long as possible. Such footballers are a valuable and performance-enhancing resource of a national team. A mixture of players from a limited number of leagues is also conducive to success.

2. However, in order to exploit players’ international experience to maximum effect, coaches should not select players from too many different leagues; even less so if they have little foreign experience. National teams which combine too great a diversity of players’ short foreign stints suffer from excessive efforts to achieve integration in terms of the game and, on average, are less successful.