The study reviews U23 players currently present in 31 top division leagues in Europe. Footballers are ranked according to the level of experience gained since the start of their career at adult level. Among players listed, notably are two goalkeepers who were born in 1999: Gianluigi Donnarumma (Milan) and Alban Lafont (Toulouse).

The method of experience capital allows clubs to optimise their approach regarding transfers by considerably reducing the risks inherent in such operations, from both the sporting and economic point of view. For recruiting clubs, there is indeed no better guarantee than recruiting footballers who have had the opportunity to play as often as possible at the highest possible level taking into account their age and talent.

Our research team is at the service of clubs interested in finding out more about the practical modalities of implementing a talent spotting system of this kind.

The English Premier League does not only gather the highest percentage of foreign players (see the 12th edition of the CIES Football Observatory Monthly Report), but it is also that where the most footballers were recruited from abroad: 43.1%. This percentage is only 31.2% for the French Ligue 1, while the big-5 league average is 36.5%.

The clubs per league who signed the highest proportion of their current squad members from foreign teams are Chelsea (75.0%), Monaco (73.1%), Lazio (67.9%), Sevilla (64.3%) and Bayern Munich (54.2%).

In total, 23 teams big-5 league teams out of 98 recruited at least half of their first team players from abroad: eight in England, five in both Spain and Italy, three in Germany and two in France. The data for all clubs is available in issue number 144 of the CIES Football Observatory Big-5 Weekly Post.

Since last June, Didier Deschamps has fielded 35 footballers who played during the current season in the big-5 leagues (34 for England). So far, they have on average played 1,913 domestic league minutes, which is about 21 matches per player. These figures are 1,585 and 17 for English national A-team players.

Up until now, the employer clubs of big-5 league players fielded by France have achieved 1.72 points per match. The highest value was recorded for teams of Spanish internationals (1.95), ahead of clubs employing footballers representing Germany (1.79) and Italy (1.77). On average, teams of English internationals achieved so far 1.61 points per match. This is only the 9th highest level among teams qualified.

The figures for all countries are available in issue number 143 of the Big-5 Weekly Post. For more information, the 11th CIES Football Observatory Monthly Report presents the squad profile of the 50 most competitive national A-teams at worldwide level. It notably shows that England fielded the youngest players in 2015 at European level.

The second coach with the longest stay at the head of his current club is Christophe Galtier at St-Etienne: 75 months. At the top of the tables in the other leagues are Giampiero Ventura (Torino, 57 months), Diego Simeone (Atlético Madrid, 51 months) and Markus Weinzierl (Augsburg, 45 months).

The median values per league vary between 16 months in the French Ligue 1 and only 9 months in the Italian Serie A. In the latter country, it is not unusual that clubs change many coaches during the same season. This reflects the lack of strategic vision of club officials more than any form of incompetence of coaches.

Between 1st July 2009 and 31st December 2015, footballers who did not yet celebrate their 22nd birthday played 14.6% of domestic league minutes in 31 top divisions throughout Europe. This percentage varies from 28.7% in Croatia to 6.1% in Cyprus. The highest value at big-5 league level was observed in the German Bundesliga (14.5%). This is almost twice as much as in the English Premier League and the Italian Serie A (7.5%).

At club level, the highest figures for teams always present in the top division league of their country during the period analysed were measured for Lokomotiva Zagreb (54.2%), OFK Belgrade (43.0%) and Feyenoord Rotterdam (39.8%). The record level in the big-5 was registered for Schalke 04 (25.0%), ahead of Toulouse (24.2%) and Bayer Leverkusen (20.7%). The record value in the English Premier League was at Liverpool (14.7%).

The Report also presents the lowest values of minutes played by U22 national footballers. AEL Limassol fielded young nationals for the fewest percentage of minutes (0.2%), followed by Stoke City and Juventus (both 0.4%). This figure was very low also at Chelsea (0.5%) and Manchester City (1.4%). Many other teams recently qualified for the Champions League are not concerned about giving young nationals their chance: Naples, Rome, Zenit, Fenerbahçe, Porto, etc.

Issue number 141 of the Big-5 Weekly Post presents the most experienced players born in or after 1995. Experience is calculated on the basis of domestic league matches played since the start of the career at adult level, weighted according to the sporting level of employer clubs. For more information about the experience capital approach exclusively developed by the CIES Football Observatory research team, please refer to the second edition of the Monthly Report.

Six players born in 1997 employed by clubs outside the big-5 leagues have a greater experience than any footballer born in the same year playing in the five major championships: Rúben Neves (Porto), Youri Tielemans (Anderlecht), Breel Embolo (Basle), Enes Ünal (NAC Breda, on loan from Manchester City), Ante ?ori? (Dinamo Zagreb) and Renato Sanches (Benfica). Sooner or later, they all should be able to settle in the most competitive leagues.

The top-10 tables for both players in the big-5 leagues and outside the five major European championships are presented in issue number 141 of the Big-5 Weekly Post. More information is available on request.

Francesco Totti is the big-5 league player who has been for the longest period in the club where he made his debut. The 39 year-old Italian is playing his 24th season at Rome. Conversely, his former teammate both at Rome and in the Italian national team Luca Toni already played for 15 clubs over his career. Both players were in the starting line-up of the 2006 World Cup final won against France.

The youngest player among the 28 big-5 league footballers who played for 10 or more clubs since the beginning of their professional career is the new Newcastle United signing Andros Townsend. While only aged 24, the English international already played for 11 teams: Tottenham Hotspur, Yeovil Town, Leyton Orient, Milton Keynes Dons, Ipswich Town, Watford, Millwall, Leeds, Birmingham City, Queens Park Rangers and Newcastle United.

The full lists are available here.

Overall, the current squad member of a big-5 league club who played the most domestic league games during his career is Leicester City’s goalkeeper Mark Schwarzer: 626 matches. Two other goalkeepers have already played more than 600 championship games over their career: Gianluigi Buffon (Juventus) and Kelvin Davis (Southampton).

Cristiano Ronaldo is second among players born in 1985 behind Bournemouth’s Simon Francis and ahead of Wayne Rooney. The top-3 tables are available in issue number 139 of the CES Football Observatory Big-5 Weekly Post. The analysis includes B-team matches.

The players listed below head the ranking for their age group.

Born on 1996 or after
Dele Alli, Tottenham, 98 matches
Born on 1995
Samu Castillejo, Villarreal, 129 matches
Born on 1994
Nathan Redmond, Norwich, 163 matches
Born on 1993
Romelu Lukaku, Everton, 210 matches
Born on 1992
Koke Resurrección, Atlético Madrid, 236 matches
Born on 1991
Eden Hazard, Chelsea, 277 matches
Born on 1990
James McCarthy, Everton, 295 matches
Born on 1989
Charlie Austin, Southampton, 320 matches
Born on 1988
Sergio Agüero, Manchester City, 368 matches
Born on 1987
Billy Jones, Sunderland, 395 matches
Born on 1986
James Milner, Liverpool, 410 matches
Born on 1985
Simon Francis, Bournemouth, 460 matches
Born on 1984
Wes Morgan, Leicester, 527 matches
Born on 1983
Jon Walters, Stoke City, 456 matches
Born on 1982
Rickie Lambert, West Bromwich, 597 matches
Born on 1981
Gareth Barry, Everton, 588 matches
Born on 1980
Sylvain Armand, Stade Rennais, 522 matches
Born on 1979
Massimo Maccarone, Empoli FC, 539 matches
Born on 1978
Gianluigi Buffon, Juventus, 612 matches
Born on 1977 or before
Mark Schwarzer, Leicester City FC, 626 matches

The U21 footballers listed below have played the highest percentage of minutes per position. Among them are notably two Schalke 04 players: Leon Goretzka and Maximilian Meyer. The latter footballer outranks his teammate Leroy Sané among attacking midfielders. The full tables are available here.

Goalkeepers

Gianluigi Donnarumma (Milan), born in 1999, 68.0%

Centre backs

Niklas Süle (Hoffenheim), born in 1995, 100.0%

Full backs

Héctor Bellerín (Arsenal), born in 1995, 92.3%

Defensive midfielders

Leon Goretzka (Schalke 04), born in 1995, 82.5%

Attacking midfielders

Maximilian Meyer (Schalke 04), born in 1995, 78.8%

Forwards

Anthony Martial (Manchester United/Monaco), born in 1995, 89.6%

The biggest performance gap was measured between Real Madrid and Rome: +32%. Atlético Madrid and Bayern Munich also performed significantly better than PSV Eindhoven and Juventus: +25%, respectively +23%. Manchester City and Barcelona outperformed Dinamo Kiev and Arsenal by 11%, while the performance level of Chelsea was 10% higher than that of Paris St-Germain.

According to the analysis of the CIES Football Observatory, the matches with the most uncertain outcome will oppose Gent and Wolfsburg (+3% for the Belgian club), as well as Benfica and Zenit St-Petersburg (+6% for the Portuguese side). Data used for the present research were provided by OptaPro. Click here for more information about the approach of the CIES Football Observatory for sustainable success.

Foreign players are much more numerous in Europe (47.7% of squads) and in the MLS (48.5%) than in Asia (17.9%) and South America (13.6%). Great discrepancies also exist according to position. While foreign footballers account for 34.9% of forwards, they only represent 20.5% of goalkeepers. The relative presence of foreign players among defenders and midfielders is around 25%.

From an age perspective, foreign footballers in the leagues studied are on average older than nationals: 27.1 years compared to 25.7. While only 13.2% of U21 footballers are foreigners, the latter represent 33.8% of players over 28 years of age. Nevertheless, the average age of first migration tends to diminish in relationship with the international recruitment of a greater number of very young players.

In six European leagues surveyed, more than half of teams are made up of foreign players: England, Belgium, Italy, Turkey, Portugal and Germany. At the opposite end of the spectrum, foreign players account for less than 10% of squads in Brazil, Uruguay, Venezuela, Costa Rica, Colombia, Argentina, Paraguay, Uzbekistan and Iran.

The study also warns the wealthiest clubs against the risk of abandoning the training of local players in favour of their import. The Report reminds that “all the clubs having left their mark on modern football in Europe (Real Madrid, Ajax, Bayern Munich, Milan, Manchester United, Barcelona) and elsewhere (Boca Juniors, River Plate, Santos, Flamengo) had several home-grown pillars, whose presence made a major contribution to their legendary status”.

The Report concludes that “talented players are born all over the world. What is missing in the first instance, is not so much talents, as a favourable context for their development. So as to encourage clubs worldwide not to take the easy road and fall into the trap of recklessly importing players and selling their souls to the market actors, training must be better protected and better paid”.

In 34 cases out of 49, the gap between the fee invested to recruit a big-5 league player and his estimated transfer value was less than 2 million €. The strong correlation between fees paid and predicted (76%) confirms the accuracy of the algorithm created from the analysis of more than 1,500 paying fee transfers occurred since 2010.

Our study allows us highlighting the payment of much higher or, more rarely, lower transfer compensations than fees paid in the recent past for players with similar characteristics. The inflation in transfer costs compared to the 11 previous transfer windows was 28%.

According to our estimates, the most over-paid player was Jackson Martínez: 42 million € instead of 18.2 (+23.8 million €). Among the five most over-paid footballers are another player transferred to China, Ramires (+10.8 million €), as well as three footballers signed by English Premier League clubs: Lewis Grabban (+7.8 million €), Timm Klose (+7.5) and Andros Townsend (+7.0).

The most under-paid player was also transferred between Premier League clubs: Jonjo Shelvey. According to our analysis, while the transfer value of the young English national A-team midfielder was 30.9 million €, Newcastle was able to sign him for "only" 16 million € (-14.9). The transfers of Mario Suárez to Watford and Augusto Fernández to Atlético Madrid were also cheaper than expected.

The figures for all big-5 league footballers transferred for money in January is available in issue number 136 of the Big-5 Weekly Post. For more information about the CIES Football Observatory approach, please refer to Monthly Reports number 6 and number 7. A transfer value calculator for big-5 league players is also freely available online.

Previous research from the CIES Football Observatory suggests that sticking on a core group of footballers often allows clubs obtaining top level results. No team who heads the table in its respective league used more than 24 players. This figure is 20 for Napoli, 22 for Leicester and Bayern Munich, 23 for Paris St-Germain and 24 for Barcelona.

Conversely, frequent line-up changes tend to reflect anxiety which is detrimental to the improvement of results. So far, clubs at the bottom of the table in their respective league on average fielded 26.0 players. This figure is 22.2 for clubs heading the table, 23.6 for the top three ranked teams per league and 25.3 at big-5 league level.

The indicator of the grip on the game refers to the number and location of passes achieved compared to opponents, while that of dangerousness is the ratio between the number and quality of shots attempted and conceded. More information about the CIES Football Observatory collective key performance indicators is available in issues number five and number seven of the Monthly Report.

The average value between grip on the game and dangerousness results in a composite indicator which allows us measuring the level of dominance of teams and estimating in an objective way the number of points that a club should have obtained accordingly. The comparison between points estimated and achieved permits us highlighting the most and least efficient teams. Future will tell what is the part of luck for the most efficient teams and that of bad luck for the most inefficient ones.

The most efficient big-5 league club so far was Stoke City. With a dominance of 0.53, the Premier League team should have obtained 0.72 points per match, which is 0.78 less than it was actually the case. At second position in the big-5 and at the top of the Liga table is Villarreal. Their dominance was 0.89, which should have allowed them obtaining only 1.24 points per match instead of 2.0 (+0.76).

Issue number 133 of the Big-5 Weekly Post also presents the data for grip on the game, dangerousness and dominance of all teams. The latter indicator suggests that the favourite clubs for the European club competitions are Bayern Munich for the Champions League and Napoli for the Europa League. Manchester City is at the top of the English Premier League table ahead of Leicester and Arsenal.

Dominance ranking

1) Bayern Munich 4.02
2) Naples 3.06
3) Paris St-Germain 2.14
4) Manchester City 2.11
5) Dortmund 2.10
6) Barcelona 2.00
7) Fiorentina 1.89
8) Real Madrid 1.87
9) Juventus 1.68
10) Atlético Madrid 1.66
11) Leicester 1.64
12) Arsenal 1.59

The average age on the pitch recorded for England during matches played in 2015 was 25.6 years. In Europe, only the Netherlands fielded footballers as young as the English ones. The youthfulness of the players available to Roy Hodgson is the sign of a renaissance which prefigures a promising future. At the opposite end of the spectrum, Scotland fielded the most seasoned footballers: 29.0 years on average.

The analysis on height shows that the average full international is 181.9cm. Great discrepancies exist between national teams. The average height on the pitch of the country who fielded the tallest players, Serbia, was 10cm greater than that of the country who played with the shortest footballers, Chile: 185.6 compared to 175.6cm. However, the short stature of the Chileans did not stop them winning the Copa América.

With regard to clubs employing internationals of the most competitive nations, the study shows the great concentration of talent in the wealthiest leagues. Almost one minute out of two was played by big-5 league footballers. In total, 68.9% of minutes were played by footballers under contract with foreign clubs. England is the only squad who did not field footballers playing abroad.

Finally, the Report highlights that 11.3% of national A-team footballers were born outside of the association represented. Two countries heavily relied on players born abroad: Algeria and Albania. Algeria fielded 21 players born in France, while 17 foreign-born footballers played for Albania. In the global era, the disjuncture between the country of birth and that represented will probably strengthen in the years to come.

Find out the other CIES Football Observatory Monthly Reports here.

During this season, footballers with national A-team caps in 2015 played 90% of domestic league minutes at Real Madrid. This figure is above 80 % for five other big-5 league clubs, four English Premier League teams (Chelsea, Manchester City, Manchester United and Tottenham), as well as Juventus. The only big-5 league team who did not field players with national A-team caps in 2015 is the Italian side Carpi.

The average percentage of minutes by active internationals per league varies between 58% in the English Premier League and 24% in the Spanish Liga. The figures for the three remaining big-5 leagues are 40% in the German Bundesliga, 31% in the Italian Serie A and 29% in the French Ligue 1. The overall percentage at big-5 league level is 36%.

Tomorrow, the CIES Football Observatory will publish the first Monthly Report of the year 2016 focusing on the squad profile of the best performing national A-teams.

The valuation is based on an econometric model created by the CIES Football Observatory research team from the analysis of over 1,500 paying fee transfers occurred since 2010. The criteria taken into account refer to both the performance and personal characteristics of players (age, position, contract duration, etc.), as well as to the competition level and results of their employer club and national team represented (if any).

More information on the indicators included in the algorithm is available in the sixth edition of the CIES Football Observatory Monthly Report. Moreover, a player value calculator is freely available online here. It is based on a less sophisticated algorithm including only data accessible to the general public. Although less precise than the statistical model used for these estimates, its predictive power is also high.

The estimated transfer value of Lionel Messi, 251 million €, is 17 million € below that of last June. This is mainly due to the fact that the Argentinean prodigy, who will turn 29 next June, has entered the final phase of his career. Despite outstanding performance levels and transfer cost inflation, his value probably already reached a peak.

Contrary to Messi’s transfer value, that of Neymar has heavily increased since June 2015: from 94 to 153 million €. In 2015, the 23-year-old Brazilian scored 25 goals in 34 appearances in the Spanish Liga, as well as 9 goals in 12 matches at Champions League level. A further increase in Neymar’s transfer value will depend on the outcome of negotiations concerning his contract at Barcelona, which currently runs until 2018.

The third highest transfer value recorded was for Eden Hazard. As for Messi, the value of the Belgian star decreased since June 2015: from 142 to 130 million €. This is mainly due to the poor performances of Chelsea during the first semester of the current season. Hazard himself did not perform at his best. However, the attacking midfielder, recently also fielded as a forward, is still a sure value of world football.

In fourth position is Cristiano Ronaldo. The transfer value of the Portuguese went also slightly down since last June: from 119 to “only” 114 million €. This is mainly due to the age factor: Real Madrid’s striker is set to turn 31 next February. With Santi Cazorla, Ronaldo is the only player aged 30 or over in the top 100 positions of the ranking. This reflects his outstanding talent and performances.

The fifth most valuable player is Harry Kane: 91 million €. This is 35 million € more than in June 2015. During the first months of the current season, the 22 year-old-striker confirmed his extraordinary skills. Moreover, the good results achieved by his employer club, Tottenham, contributed to increase his value. With the same performances on an individual level and Champions League qualification, Kane’s value will probably reach the 100-million € mark at the end of the season.

From sixth to tenth position are other top class attacking players: Raheem Sterling, Antoine Griezmann, Luis Suárez, Sergio Agüero and Alexis Sánchez. The transfer values of Anthony Martial, Paul Pogba, Kevin de Bruyne, Philippe Coutinho and Thomas Müller are also above 70 million €, while those of Robert Lewandowski, Gareth Bale and Romelu Lukaku are just below.

The top 100 list is freely available on the CIES Football Observatory’s website. The data on the 30 most valuable big-5 league club teenagers is available on request at football.observatory@cies.ch.

The analysis of the CIES Football Observatory is 100% data-driven from statistics provided by OptaPro. It takes into account the technical performance of players at big-5 league level since January 1st 2015 in six key areas of the game. More explanations are available in issue number 5 of the Monthly Report. From a broader perspective, the 7th Report presents the exclusive CIES Football Observatory approach for sustainable success.

Outfield players are divided into six positions: centre backs, full backs, defence-oriented central midfielders, attack-oriented central midfielders, attacking midfielders and forwards. Only footballers who played at least 2,250 minutes, equivalent to 25 full big-5 league matches, were included in the rankings.

On the basis of our analysis, the CIES Football Observatory dream team (4-2-3-1) is composed as follows: Neuer; D. Alves, T. Silva, Chiellini, Monreal; Gündogan, Cazorla; Özil, de Bruyne, Hazard; Messi. The dream team for U23 players, born after 1st January 1993, is composed as such: Karius; Bellerín, Umiti, Varane, Wendell; Tolisso, Pogba; B. Silva, Barkley, F. Anderson; Dybala.

Despite top level performances, several players do not appear in the tables as they were not fielded for at least 2,250 minutes in big-5 league games in 2015. This is notably the case of Z. Ibrahimovi?, M. Salah and S. Agüero among forwards; D. Silva, J. Navas and D. Perotti among attacking midfielders; M. Verratti, Y. Touré and A. Ramsey among central midfielders; L. Kurzawa, A. Kolarov and J. Alba among full backs; as well as D. Luiz, J. Boateng and D. Alaba among centre backs.

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

Seven out of the 10 top ranked clubs qualified for the Champions League knockout stage. The only exceptions are Manchester United, Tottenham Hotspur and Inter Milan. The last two clubs did not even participate in the competition. However, the Italian side is currently at the top of the Serie A table.

Real Madrid is the team with the most footballers with national A-team caps in 2015: 19 players. At second position is Manchester United (18). Louis van Gaal’s team outranks Chelsea, Tottenham and Juventus (17 players each). In total, Manchester United players represented 10 national selections. Sergio Romero played more games for Argentina (13) than for Manchester United (4).

List of players

• Sergio Romero, 13 matches for Argentina
• Marcos Rojo, 11 matches for Argentina
• M. Darmian, 10 matches for Italy
• Daley Blind, 9 matches for the Netherlands
• Wayne Rooney, 8 matches for England
• Morgan Schneiderlin, 8 matches for France
• Memphis Depay, 8 matches for the Netherlands
• Phil Jones, 7 matches for England
• Bastian Schweinsteiger, 6 matches for Germany
• Chris Smalling, 6 matches for England
• Anthony Martial, 6 matches for France
• Marouane Fellaini, 6 matches for Belgium
• Patrick McNair, 5 matches for Northern Ireland
• Antonio Valencia, 4 matches for Ecuador
• Juan Mata, 4 matches for Spain
• David De Gea, 4 matches for Spain
• Michael Carrick, 3 matches for England
• Luke Shaw, 2 matches for England

Nowadays, throughout Europe, players with the disadvantages of being born in the last months of the year and of later physical development have little chance of pursuing a career at a high level. The authors recommend to organisations in charge of the development of youth players and the game to “take the question of the relative age effect seriously”.

According to the Report, the limiting of the selection bias linked to the date of birth and to the level of physical development would reinforce meritocracy in football. Over the long term, such a step forward would be beneficial not only to the level of spectacle that teams are able to provide, but also on the level of balance of competitions.

English players are the only ones born on average after July 1st, the average date of birth of a typical citizen. This can be explained by the fact that age classes in English football are based on the cut-off date used by the school system, the 1st September, and not the 1st January as in other countries. Consequently, the least represented players among English professional footballers are those born in August and not in December as in the 30 other associations surveyed.

Issue number 128 of the Big-5 Weekly Post presents the data on the average day of birth of players for each club of the five major European leagues. In 23 teams only, this date is after July 1st. The extreme values were recorded at Fiorentina (20 April) and Southampton (11 August).

In two other clubs only, the average transfer expenditure for player on the pitch is above 20 million €: Chelsea (21.9) and Barcelona (21.3). This figure goes down to 16.1 million € at Arsenal, 15.8 million € at Liverpool, 11.1 million € at Tottenham … and 2.5 million € for Leicester City.

On average, Bayern Munich (15.4 million €) and Juventus (14.4 million €) also spent only half per player than Real Madrid, Manchester City, Manchester United and Paris St-Germain. This finding highlights the great discrepancies existing up to the very top of the football pyramid.

All the data is available here.

In total, the 2,165 footballers fielded so far by big-5 league teams have played in 1,276 clubs from the start of their career at adult level to their 23rd birthday. At the top of the table of teams having contributed most to the development of these players is Real Madrid Castilla. Up until 23 years of age, 45 footballers under contract with big-5 league teams have played for the team currently coached by Zinédine Zidane. Among them, we notably find Juan Mata (Manchester United), Alvaro Negredo (Valencia) and Roberto Soldado (Villarreal).

For comparability reasons, the player development index only considers domestic league games. A match played before the age of 21 is weighted double with respect to a game played between 21 and 23 years of age. Moreover, the values are weighted according to the current employment rate of players in order to give more weight to teams having developed the most fielded footballers.

The team who contributed most to the development of Premier League players is Southampton, followed by Aston Villa and Dutch side Ajax Amsterdam. Chelsea and Everton also rank in the top five positions.

At the top of the tables in the remaining big-5 leagues are Empoli for Italian Serie A players, Bayer Leverkusen for German Bundesliga, Barcelona B for Spanish Liga and Olympique Lyonnais for French Ligue 1 footballers. Issue number 126 of the CIES Football Observatory Big-5 Weekly Post presents the data for the top 40 clubs per league.

The player development index could be particularly useful for leagues, national associations and international football governing bodies to set up systems of financial equalisation and/or reward mechanisms incentivising more teams to promote both the training and fielding of young talents. Over the long term, this would have a positive effect on football as a whole.

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

The CIES Football Observatory Digital Atlas presents league and club rankings for eight indicators:

• Average age: the oldest top division league in Europe is Turkey (27.3 years), while the youngest is Croatia (23.9 years). At club level, Chievo Verona is composed of the oldest players (30.6 years). Hajduk Split and Senica have the youngest squad (22.1 years).

• Average height: the tallest top division leagues at European level are in Germany and Croatia (183.3 cm). The shortest players are to be found in Israel (180.1 cm). There is a 9 cm gap between the tallest and shortest club: Wolfsburg (187.0 cm) and Ludogorets Razgrad (178.0 cm).

• Average stay: the most stable league from a player turnover perspective is England. Squad members have been in the first team of their employer team for 2.82 years on average. At the opposite end of the table is Serbia (1.71 years). The most and least stable clubs are CSKA Moskow (5.7 years) and Chornomorets Odessa (1.2 years).

• New signings: clubs in Romania signed the most players since January 1st 2015: 14 per club on average. At the other end of the spectrum is Sweden (7.4 players). At club level, the record high was recorded at Bologna (23 players), while the record low was measured for Karpaty Lviv and Metalurg Zaporizhya (1 player).

• Debutants: on average, European top division clubs launched 1.04 players without previous experience in the professional game: from 2.29 in Ukraine to 0.13 in Greece. Metalurg Zaporizhya holds the record at club level with 11 debutants. However, they are currently at the bottom of the Ukrainian Premier League table.

• Club-trained: the top division league in Belarus has the highest percentage of club-trained players (34.0%). Inversely, in Turkey, players who have been in their employer club for at least three seasons between the ages of 15 and 21 only account for 8.3% of squad members. The record high at club level was observed at Gomel (91.7%). More information is presented in the ninth edition of the CIES Football Observatory Monthly Report.

• Expatriates: the top division league with the highest percentage of expatriate players is that of Cyprus (66.4%). The lowest proportion of expatriates was recorded in Serbia (15.7%). Expatriate footballers account for up to 88.0% of squad members at Slovenian side NK Zavr?. Only three teams out of 460 have no expatriates: HIFK Helsinki, FK Gomel and FK P?íbram.

• Active internationals: the English Premier League gathers the highest percentage of players with national A-team caps since the start of the season (41.4%). This percentage is only 2.0% in Slovenia. The club composed of the greatest proportion of active internationals is Manchester United (72.0%).

Following UEFA’s definition, club-trained players are footballers who have been for at least three seasons between the ages of 15 and 21 in their employer team. The relative presence of this category of players in squads has steadily decreased from 23.1% in 2009 to only 19.7% in 2015. Club-trained footballers still accounted for more than one fifth of squad members in 2014: 21.0%.

This finding reflects the lesser tendency of European top division clubs to give their chance to players from their youth academy. As a consequence, the average age of footballers in the 31 top division leagues surveyed has reached a new record high: 26.0 years. The decrease in the proportion of club-trained players also reflects the greater mobility of footballers from their youngest age.

The Report also presents the rankings of clubs who trained the most players active in the leagues surveyed. At the top of the overall table is Partizan Belgrade (78 players trained), followed by Ajax Amsterdam (75 players). FC Barcelona heads the ranking of clubs who trained the most players under contract with big-5 league teams (44 players), ahead of Olympique Lyonnais (35 players) and Real Madrid (34 players). All data is available in issue number 125 of the Big-5 Weekly Post.

Last but not least, the CIES Football Observatory is pleased to unveil a brand new version of its exclusive Digital Atlas on the demography of footballers in Europe. This unique tool presents a wide array of indicators allowing users to grasp the latest trends in the European football players’ labour market. The next Monthly Reports will further develop some of the exclusive information presented in the Digital Atlas.

The CIES Football Observatory warmly thanks its growing audience for the interest and positive feedback received. The authors of the Report - Drs Raffaele Poli, Loïc Ravenel and Roger Besson - are at the disposal of media at football.observatory@cies.ch.

The first position held by Otamendi in the centre back table is mainly related to his outstanding skills in the area of rigour (see explanation below). At full back level, Aurier performed particularly well from a recovery perspective. Cazorla outranks all defensive midfielders mainly thanks to his statistics in the area of distribution. Among attacking midfielders, Özil has no rivals in terms of chance creation. Finally, shooting is the key strength of Lewandowski compared to other forwards.

The rankings are based on a purely data-driven and objective methodology developed by the CIES Football Observatory research team. The Key Performance Indicators (KPIs) considered measure players’ productivity in six complementary areas of the game. The final score is the sum of values measured in each area, weighted according to the importance of the latter for a given position. Only players fielded for at least 60% of domestic league minutes are included in the rankings.

A thorough presentation of the CIES Football Observatory approach for the technical analysis of performance is available in the fifth edition of the Monthly Report.

CIES Football Observatory KPIs

• Rigour: ability to minimise goal opportunities for opponents through effective duelling.
• Recovery: ability to minimise goal opportunities for opponents through proficient interception work.
• Distribution: ability to keep a hold on the game through efficient passing.
• Take on: ability to create dangerous situations by successfully challenging opponents.
• Chance creation: ability to put teammates in a favourable position to strike.
• Shooting: ability to take advantage of goal opportunities through accurate shooting.

At second and third position in the English Premier League ranking are Liverpool (25.5 years) and Newcastle (25.6). In contrast, the average age on the pitch is particularly high at West Bromwich Albion (29.2) and Manchester City (28.5).

The oldest teams in the other big-5 leagues are Rayo Vallecano (29.0 years), Bastia (28.6), Darmstadt (28.1) and Chievo (30.7). The average per league varies between 26.3 years in the German Bundesliga and 27.5 years in the Italian Serie A.

The most numerous contingent of French expatriates is to be found in England. Since the start of the season, 40 players from France played in the English Premier League. However, French are well represented also in Italy (28 players), Spain (27 players), and, to a lesser extent, Germany (11 players, including Kingsley Coman who also played in Serie A).

The analysis of countries with the most representatives in foreign leagues at worldwide level is available in the eighth edition of the CIES Football Observatory Monthly Report. For more information, please contact us at football.observatory@cies.ch

While Brazil is the most represented origin among foreigners both in Europe (1,137 players) and in Asia (437 players), Argentina is the main exporting country at Latin American level (511 players compared to only 124 Brazilians).

At worldwide level, the three nations with the most footballers in foreign professional and semi-professional clubs are Brazil (1,784 players), Argentina (929 players) and France (758 players). These three nationalities alone account for almost 20% of foreigners present on a global level.

No South American country is among the top five destinations of Brazilians. Conversely, three of the five main destinations of Argentineans are to be found in South America. Similarly, the main countries to which French players migrate are geographically close to the home country.

The last chapter of the study analyses four leagues in the United States, where football is undergoing considerable development. The Report shows the marked diversification of international recruitment of US clubs. It also predicts that American teams will increasingly challenge European, Asian and South American clubs in the race for new talent.

For more information or to contact the authors of the study, please write to football.observatory@cies.ch

Conversely, the most positive difference so far between financial and sporting ranking in the English Premier League was measured for Leicester City: +12. Claudio Ranieri’s team is in fifth position, while only three EPL clubs invested less money to assemble the squad.

In the other big-5 leagues, the teams that over-achieved the most with respect to transfer investments are Eibar (+10 positions), Angers (+17), Ingolstadt (+11) and Chievo (+8).

On the contrary, the following teams are currently ranked well below the position where their financial power should have allowed them to be: Real Sociedad (-11 positions), Marseille (-13), Stuttgart (-8) and Juventus (-11).

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.