KPI’s can be derived from event data within game moments by using the What-Who-How (W-W-H) model. To assess team performance in football, KPI’s are measured within game moments, namely:
1) In-Possession
2) Out-of-Possession
3) Transition (Ball is being disputed in transition)
4) Restarts (Throw-in, Goal Kicks, Set Plays)
1) In-Possession
The What: Understanding Team Style as a Measure of Time spent
Team style measured as a function of time spent would help evaluate The What, i.e. effectiveness of a team playing style (Proactive OR Reactive) within a given phase of play. After dividing the football pitch into thirds (Defensive, Middle, Attacking) and measuring the time spent in these areas, provides one part of a holistic view in understanding team strategy. It can be used as a measure of comparison to opposition teams and different leagues. A measure of momentum will evaluate areas of the pitch where teams increase their tempo in either of the phases of play. Time spent in the sustained possession phase would provide evidence to where & when teams retain possession the most. Essentially, combining one or more measures can give a decisive picture of time spent playing a certain way. The table below indicates the KPI’s measured through event data:
The time spent in different areas of the pitch can provide actionable insight to questions such as:
1) Which areas of the pitch does the team turn up the momentum of play?
2) Where do they retain possession the most?
3) Does the team sustain possession in the opposition half for long periods?
4) How often do they play counterattacking football at pace?
The How: Understanding Team Styles by measuring Actions through zones
A measure of actions involved in different phases of play breaks down the How in understanding team styles. By splitting the pitch into horizontal zones (Half-space, Wing, Centre) in addition to splitting them vertically (Defensive, Middle, Final) provides insight into a team’s actions. It would define the threat generated by teams in the final third, actions involved prior to penetration into the final third and building out from the back. Measuring success of these actions can evaluate team performance and provide a measure of success to team strategy. The resulting KPI’s would answer a few related questions such as:
1) What is effectiveness of in-swinging and out-swinging crosses?
2) How does a team build up from the back?
The table below examines the KPI’s measured as % of actions across horizontal and vertical zones:
The Who: Understanding players making up playing style
Identifying players who are most involved in playing style as a function of ball receptions & actions provides added context to the above-mentioned sub-styles. This in-turn can evaluate if a team has specific players positioned in key roles for the team or if they’re better off playing in another position. By analysing players on-the-ball actions distributed over their playing positions would provide insights such as:
1) The preference of a player actions related to success % in a specific area
2) The likelihood of a player’s consequent action given his previous two actions
3) Defining a role of player within phases of play to analyse the best fit position
2) Out-of-Possession:
Since event data consists of on-the-ball actions, it’s quite difficult to analyse team performance through defensive actions. (Lotte Bransen & Jan Van Haaren, 2020) proposed a model to understand joint defensive impact which is relevant for scouting purposes. Successful Defensive actions can be defined based on four ball winning moments:
1) Successful Tackle, Possession won (Ball Recovery in the next action)
2) Interceptions that led to a Ball Recovery by same/different player in the next action
3) Ball Recovery (Picking up a loose ball after different preliminary actions)
By analysing ball winning moments using WWH model, KPI’s can be derived to analyse ball winning zones or pressure zones using the pressure metric, define roles for players picking up a loose ball repeatedly and interceptions made by players in specific areas. Measuring intensity of pressure can be done by analysing the number of passes made by the offensive team (PPDA- Passes allowed per defensive action) before the defensive team try to win the ball back.
3) Transition:
Given transition is a moment when the ball is being disputed, the following KPI’s can be measured:
1) Aerial Duels Won – Aerial Duels Win %,
2) Ground Duels- Ground duels Win %
3) Loose Balls: Loose Ball Win %
4) Restarts: Set Plays, Goal Kicks & Throw-ins
W-W-H (What-Who-How) Model
The What-Who-How (W-W-H) model is widely used within the business context mentioned here and within the coaching context mentioned here. The WWH model is a structured approach to develop KPI’s based on player performance in relation team strategy by measuring individual performance, analysing opposition team strategy, and providing evidence-based findings to existing coaching principles. The What would effectively describe a team’s playing style (Proactive OR Reactive) based on a measure of time within a given phase of play. The Who would describe players actions that contribute to a team’s playing style and can essentially explain if a player is best fit for a team. The How explains the way teams attack or defend through their actions in specific areas (zones). Thus, the following approach creates a comprehensive model to analyse team and player performance.
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