Advanced metrics: Sequences framework

Posted 23rd August 2019

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Learn more about Opta's sequences framework

As part of Opta’s commitment to offering greater detail to sports fans across the world, we develop advanced metrics such as expected goals, helping to explain the game in more detail.

Historically, metrics have revolved around independent moments in time such as a passes, tackles or shots. Opta’s sequence framework represents an evolution of existing models, stringing together these events into sequences. This provides a more detailed picture of what is happening on the pitch. See our explainer video here:

Sequences are defined as passages of play which belong to one team and are ended by defensive actions, stoppages in play or a shot. 

Possessions are defined as one or more sequences in a row belonging to the same team. A series of passes leading to a shot which is saved, and results in a corner, would comprise one possession, since the same team retains control. A possession is ended by the opposition gaining control of the ball.

 

Example: Roberto Firmino goal sequence

The below sequence map shows Roberto Firmino's goal vs. Brighton in the 2017/18 Premier League season. The sequences framework reveals the distance that the sequence covered, the number of passes that comprised the sequence, and the pace of the build-up to the eventual shot and resultant goal.

The map visualises how the sequence leading to Firmino's goal covered a substantial fraction of the pitch, beginning deep into Liverpool's own half, but entering Brighton's half after just two direct passes. This showcases the counter-attacking, direct playing style of the Liverpool team behind Firmino's goal.

Team playing style

Opta's sequences framework reveals a team's playing style. Looking at Sky Sports' comparison of Watford and Leicester City, we can see how the Hornets adopted Leicester's 2015/16 title-winning playing style. Both teams ranked near the top of the league in high turnovers, revealing Watford's ability to press high up the pitch, putting in a real defensive shift. The emphasis on Watford's off-the-ball work transformed them into a team that plays a lot of the game out of possession. Like Leicester, they ranked low for average possession, and sprung fast, direct counter attacks when they won the ball back. 

Measuring player contribution through sequences

Similarly, at the player level, sequences can be used to highlight the contribution of players who may not be credtied by traditional metrics. Sequences add context to traditional metrics, like tackles and interceptions, by detailing what happens next. We can use a metric derived from the sequence data to rank the top five Premier League players last season, for the number of times they initiated a sequence that resulted in a shot on goal. 

 

Top 5 players for initiating the first open play sequence in a possession that ended in a shot.

 

This metric illustrates how a player like Declan Rice, not only wins the ball back for his team, but then goes on to initiate attacking actions from these events.

Looking at the game through sequences, allows us to more effectively analyse players’ contributions and give credit to those who might have been missed in the past. Despite having zero assists for the 2018/19 season, Declan Rice was clearly an influential player in West Ham's attacking movements. 

To learn more about Opta’s sequences framework, and other advanced metrics, get in touch using the form below.

 

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