Wyscout data allow us to compute a team’s invasion index in a very efficient manner: since an event (pass, duel, shot, etc.) is characterized by a timestamp and a spatial location, we can easily split a game into possession phases and assign a weight to every event.
The Invasion Index describes how effective a team’s playing style is. To give an idea of its descriptive power, let us consider an entire season of two teams: Mourinho’s Manchester United (sixth in the last Premier League) and Gasperini’s Atalanta (fourth in the last Serie A). In Figure 2, as the season goes by we plot the difference between the Invasion index produced by Manchester United and its respective opponents. Figure 3 does the same for Atalanta. A positive value indicates that Manchester United (or Atalanta) has a higher invasion index than the opponent. For Manchester United, we find three main trends: a slow start, a growth as the season goes by, and a significant decrease at the end of the season. Atalanta shows a more fluctuating behavior, as witnessed by the higher number of negative peaks during the season.