At the top of the absolute tables in the English Premier League are Laurent Koscielny (Arsenal) for centre backs, Cédric Soares (Southampton) for full backs, Santi Cazorla (Arsenal) for defensive midfielders, Mesut Özil (Arsenal) for attacking midfielders and Riyad Mahrez (Leicester) for forwards.

The analysis relies on data provided by OptaPro and takes into account performance in six key areas of the game: rigour, recovery, distribution, take on, chance creation and shooting. A detailed presentation of the exclusive approach developed by the CIES Football Observatory research team is available in issue number 5 of the Monthly Report.

According to this approach, the best performing U21 footballers in the English Premier League so far have been Chancel Mbemba (Newcastle) for centre backs, Jordan Amavi (Aston Villa) for full backs, Emre Can (Liverpool) for defensive midfielders, Nathan Redmond (Norwich) for attacking midfielders and Raheem Sterling (Manchester City) for forwards.

The top 15 list per league and position is updated on a weekly basis on the CIES Football Observatory website. More information is available at football.observatory@cies.ch.

Clubs participating in the Champions League are over-represented in the top positions of the ranking of clubs having generated the most incomes in transferring players to other teams. Among the 15 top ranked clubs, only Monaco, Liverpool and Aston Villa did not qualify for the group stage of the 2015/16 Champions League. This finding shows the key importance to obtain top level results to be able to transfer players for significant amounts of money.

However, the majority of clubs having generated the most incomes on the transfer market are also among teams who invested the most for new signings (see issue number 118 of the CIES Football Observatory Big-5 Weekly Post). Consequently, among the 15 clubs with the most positive net transfer spend, only Wolfsburg and Sevilla take part in the group stage of the current Champions League edition.

Among the 15 clubs with the most negative net transfer spend, we find some of the wealthiest European clubs (Manchester City, Paris St-Germain, Manchester United, Real Madrid, etc.), as well as not-so-rich teams who heavily invested on the transfer market in the hope of improving results, such as Milan AC, Newcastle United, West Bromwich Albion, Bologna, Sunderland and Crystal Palace.

On average, during the last three summer transfer windows (2013-2015), the transfer expenditure of big-5 league clubs was 68% greater than in the three previous ones (2010-2012). The biggest increase was recorded at English Premier League level: +98%.

Manchester City tops the table for summer 2015 with a transfer expenditure of 230 million €, ahead of Manchester United (189 million €) and Juventus (137 million €). The transfer expenditure of English clubs (1.35 billion €, new record high) accounted for 41% of total big-5 league investments.

Manchester City also heads the ranking of transfer fees invested since July 2010: 784 million €. In second and third position are two other English clubs: Chelsea (711 million €) and Manchester United (640 million €). The first non-English club is French side Paris St-Germain (615 million €).

On average, big-5 league players transferred for money during last summer were paid 23% more than footballers with similar characteristics transferred during the five previous years. If we add this percentage to the transfer values estimated by the CIES Football Observatory at the end of the 2014/15 season on the basis of its exclusive econometric model, we obtain figures taking inflation into account.

The comparison of these values with fees paid by clubs allows us to assess transfers from an economic perspective. This analysis is carried out without considering add-on fees related to the future performance of players, nor sell-on fees negotiated on future transfers. Players on loan with buy-out clauses were not included.

This study indicates that the most under-paid player in absolute terms with respect to the sums invested in the recent past for footballers with similar characteristics was Anthony Martial by Manchester United (+27.9 million €, not including add-ons), followed by Kevin de Bruyne by Manchester City (+26.6 million €) and Christian Benteke by Liverpool (+19.6 million €).

At the opposite end of the table, the most under-paid players according to the CIES Football Observatory analysis were Raheem Sterling by Manchester City (-32.1 million €), Mapou Yanga-Mbiwa by Olympique Lyonnais (-11.9 million €) and Robin van Persie by Fenerbahçe (-11.4 million €).

More information is available on the CIES Football Observatory website or on request at football.observatory@cies.ch. For a detailed presentation of the methodology used to estimate the transfer value of players, please refer to issue number 6 of the CIES Football Observatory Monthly Report.

In total, big-5 league teams have spent a record figure of 9.3 billion euro to sign current squad members. The gaps between clubs are tremendous: from 587 million for Real Madrid to less than one million for Carpi, Frosinone, GFCO Ajaccio, Rayo Vallecano and Sporting Gijón.

From the perspective of transfer market investments, one would expect that Real Madrid, Manchester City, Paris St-Germain, Bayern Munich and Juventus win the title in their respective leagues. Conversely, at English Premier League level, Bournemouth, Watford and Norwich should face relegation just one year after promotion.

For a detailed analysis of the link between transfer expenditure and success, refer to issue number 3 of the CIES Football Observatory Monthly Report.

Since 2005, the Football Observatory research group within the International Centre for Sports Studies (CIES) has developed pioneering data analysis to understand the logics of success in football. This report unveils the key findings related to the four main dimensions of sustainable squad management: team chemistry, demographic structure, performance analysis and transfer policy.

Professional clubs, football academies and leagues regularly take advantage of the exclusive expertise gathered within the CIES Football Observatory to increase their competitiveness. The innovative research work carried out also has an educational vocation by helping football stakeholders, including media and fans, to develop original thinking on the beautiful game.

Furthermore, the CIES Football Observatory academic team is pleased to disclose its player performance rankings for the five major European championships. The top 15 list per position and league will be updated on a weekly basis throughout the season. To know more about the methodology used, see Monthly Report number 5.

For more information, please contact us at football.observatory@cies.ch.

During last season, the percentage of minutes played by club-trained footballers reached a new record low: 14.3%. In the English Premier League, players who spent at least three years between the ages of 15 and 21 in their employer club never played a fewer percentage of minutes than in 2014/15: 10.2%. The minimal level of minutes played by club-trained footballers was recorded in Italy: 8.5%.

The percentage of minutes played by expatriates is stable at around 46%. However, the percentage of players who grew up in a different country than that of their employer club reached a new record high among the five best ranked teams per league: 59.6%. This percentage was never as high as in 2014/15 in three leagues out of five: England (77.1%), Spain (57.1%) and Germany (53.1%). It is also very high in the Italian Serie A: 71.4%.

The CIES Football Observatory is also proud to be able to present for the first time the probabilities of fee paying transfers for big-5 league players. This was a major achievement of the research work carried out by our academic team during the last year. Many expensive footballers are to be found in the top-100 of this ranking, such as Raheem Sterling, Alexis Sánchez, Antoine Griezmann, Harry Kane and Philippe Coutinho.

More information is available in issue number 115 of the Big-5 Weekly Post (the last before the summer break). The full data is presented in the sixth edition of the CIES Football Observatory Monthly Report. This publication also explains the unique methodology developed by our research team to estimate both transfer values and transfer probabilities of football players.

The clubs per league having the most relied on U21 players are Monaco (34.6%), Valencia (25.5%), Empoli (23.3%), Bayer Leverkusen (23.1%) and Liverpool (19.8%). Conversely, U21 footballers played less than 2% of minutes in 27 teams out of 98, including at Champions League finalists Barcelona and Juventus.

All the data is available in issue number 113 of the CIES Football Observatory Weekly Post.

For more information, please contact us at football.observatory@cies.ch.