The 41st CIES Football Observatory Monthly Report analyses the link between ball possession and results in 35 championships from UEFA member associations using the data used generated by the specialist InStat company. Though the link between success and possession is undeniable, it is only from a certain level that ball control allows teams to improve significantly their results. This is probably the source of the erroneous but widespread idea that possession is not a key factor for success.

Competitive balance is a crucial issue for the whole of collective sports. The 40th Monthly Report of the CIES Football Observatory analyses this issue from a spatio-temporal perspective. The sample includes 24 European competitions over a period of ten seasons between 2008/09 and 2017/18. All of the indicators analysed illustrate a trend towards a greater imbalance in European football.

The long-term work carried out within the CIES Football Observatory focuses, in particular, on the demographic analysis of the football players’ labour market. The surveys carried out over the past decade allow us to reveal very clear trends. As illustrated in this report, the footballers’ labour market in Europe is becoming deterritorialised by a decreasing presence of club-trained players, a stronger presence of expatriate footballers and greater mobility.

This report analyses club strategies in the area of player turnover for the five major European leagues since 2005/06. It reveals that too many changes in line-ups do not constitute a good strategy for optimising results. On the contrary, high turnover levels tend to affect players’ confidence and aggravate the situation.

The 37th CIES Football Observatory Monthly Report analyses from a financial standpoint transfer operations carried out by big-5 league clubs since 2010. It notably highlights the key role played by the Premier League in the structuration of the market. During the eight-year period analysed, English top division clubs are responsible for 78.3% of the overall big-5 league deficit for transfer operations.

Football offers incredibly interesting possibilities to when it comes to data-driven analysis. This e-book regroups the Monthly Reports published by the CIES Football Observatory over the course of the 2017/18 season. Two research notes are also included. The contents mainly relate to our three key areas of expertise: the demography study of the players’ labour market, the analysis of the technical performance of both teams and players, as well as the economic study of the transfer market.