The Effect of Transfers on the Performance of a Football club: A Review

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Transfer window is widely expected from football fans around the globe, and particularly the summer one, where in general terms only a few competitive matches exist. The negotiations between clubs along with the conformation of the total transfer map are both intriguing for the vast majority of people and stimulate their interest towards such updates.


The current report investigates the effect of the number of transfers on the overall performance of a football club. For the sake of it, teams from the five most competitive leagues were examined, and their performance during season 2017/2018 was compared to this of season 2016/2017. The aim is to determine which clubs may benefit from potential transfers during the summer transfer window and in which ones the imbalance created from the large number of changes has a negative effect.


The transfer window is the period during the year in which a football team can transfer players from other countries into their playing staff. Such a transfer is completed by registering the player into the new club through FIFA. “Transfer window” is the unofficial term commonly used by the media for the concept of “registration period” as described in the FIFA Regulations on the Status and Transfer of Player. According to the rules, each national football association decides on the time (such as the dates) of the window, but it may not exceed 12 weeks.

The window was introduced in response to negotiations with the  European Commission. The system has been used in many European Leagues before being brought into compulsory effect by FIFA since 2002. However, the exact regulations and possible exceptions are established by each competition’s governing body rather than by the national football association.


For the purpose of the current research, data about transferred players and according costs was collected from last season (2017/2018), while the comparison of the clubs’ performance in their respective leagues was evaluated taking also into account the year before (season 2016/2017).

The leagues that were investigated consist of La Liga (Spain), Bundesliga (Germany), Premier League (England), Ligue 1 (France) and Serie A (Italy). The selection of the teams under study was arbitrary, while the number was decided to be equal to 6 for each particular competition.




Spanish teams chosen are the ones with the smallest number of changes during the summer transfer window of season 2017/2018. The total number of transfers, both sales and arrivals, was 73, with Espanyol, Valencia and Sevilla having the vast majority (43 in total).


French clubs had in total 112 modifications in their players, with Lille leading the way (25). An interesting fact is that the smallest value obtained in the number of players exchanged is 15, shared by two teams, Caen and Nice.


On the other hand, Italians are the ones with the biggest number of changes on this period, equal to 143. Inter on its own had 37 changes in its squad, followed by Roma (27) and Udinese (24). Sassuolo had surprisingly small activity on the transfer window, compared to the rest of the teams under study.


Regarding the Premier League clubs, a wide distribution is noted, as there are teams like Swansea and Watford that underwent a lot of changes in their squads, while others, such as United and Liverpool had minor alterations in personnel (6 and 9, accordingly). Overall, English teams had the second lowest number of changes during that particular transfer window.

As for the German teams, which lie somewhere in the middle (82 changes overall) a narrow dispersion is observed. The extremes are between 11 (for Leipzig) and 19 (for Leverkusen and Wolfsburg).


In the second part, an analysis was conducted in order to determine the correlation between total number of changes during the transfer window and its effect on the clubs’ performance in the domestic league competitions.


It is illustrated that teams that did not perform well during season 2016/2017, such as Valencia and Levante, were favored by the large number of changes in their squads ( 13 and 12 respectively). On the other hand, teams that managed to finish in the upper side of the table, like Espanyol and Sevilla, were affected by the addition of new players in their respective squads, and a decline in their performance as a whole is observed. Villareal, who had the smallest activity in the transfer market, actually managed to retain their 4th position in the La Liga standings.


Regarding French teams, it is concluded that traditional forces, such as Monaco, Marseille and Bordeaux, were not influenced by changes during the transfer market, as again they managed to be highly competitive and finish in a good position. The same trend is also followed by teams like Caen, who struggled to avoid relegation; the 15 changes in their team did not seem to play a crucial role in their league performance. In contrast, severe squad modifications appear to have a large effect on mid-table clubs (Lille) with exponential decrease in their corresponding performance.


In the Italian league, it had been found that changes in the squad do not directly affect the performance in the league, unless these changes reach vey high numbers, such as in the case of Inter Milan. Inter did not have a good season finishing 7th in the league and the board, along with the coaching staff, decided to proceed in radical modification of the team. The 37 total departures and arrivals was enough to establish Inter in Serie A’s top-4 in season 2017/2018.


Regarding the Premier League clubs, it is concluded that a big number of changes in the squad has a negative effect, at least for teams that battle for their presence in a European competition (Chelsea, Everton, United and Liverpool). Indicatively, United and Liverpool, with 6 and 9 alterations respectively, were improved or remained constant during this period, while severe changes, as in the case of Chelsea and Everton, showed a negative impact on their performance.

Moreover, for the German teams that finished in the top-3 of Bundesliga in 2016/2017 (Dortmund and Leipzig) modifications in the squad appeared to have a gentle decrease in their performance, while for the rest of the teams a common pattern is not obtained.


To sum up, in this study case an effort to understand the correlation between the number of transfers and the performance of a football club was employed. The results are different and depend not only on the league characteristics but also, on the overall strength of the team among its competitors. Indicatively, traditional forces in the English football, such as Liverpool and United, seem to depend on the total number of changes (the lower the better) while Italian clubs of different ranking do not appear to get affected by the activity during the summer transfer window.

BIBLIOGRAPHY (2018). Football transfers, rumours, market values, news and statistics. [online] Available at: /[Accessed 6 Jul. 2018]. (2018). Transfer window. [online] Available at: [Accessed 6 Jul. 2018].

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