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.