MLS Tacticalytic: High-Pressure Pressing

This piece is part of a bigger effort to build a matrix of measures to characterize a team’s tactical style and efficiency. Passing is the most abundant action of any soccer game. Each game averages about 500 passes, almost 90% more than any other action such as dribble or shot. The pass pattern changes when a team tries to achieve different goals; a team passes slower when they want to control the possession but passes faster (fewer touches) when they enter the shooting zone. If done properly, one can use a team’s pass pattern describe and measure its behavior(s) at any given moment.

The plot has four measures. The opponent’s defensive-third number of long passes / number of total passes (LB Ratio) measures the percentage of the long pass a team plays in the defensive third. When you press high against an opponent, you apply high pressure to the ball handler to achieve one thing: to regain the possession. You can restore the control of the ball in your opponent’s half, or you force it to clear a long ball forward. The defensive third LB Ratio measures the efficiency of the latter behavior. A long pass is unreliable; the best team in that area completes only about 50% of its long passes. Forcing an opponent to play a long pass increases your probability to regain the possession. The higher defensive pressure you apply to your opponent, the less likely its players can build-up gradually from the keeper, and the more long passes you force its defenders to play.

The opponent’s mid-third short pass success (SPS) measures the pass success an opponent has in the midfield. A short pass is reliable; its success rate is over 90%, almost 50% higher than a long pass. A high-pressure defense like pressing should disrupt the success of a short pass higher up the pitch, like the midfield. The mid-third SPS is the first of a series of similar measures; in the future, it will be compared to the similar measures in the defensive third and the final third. They together will describe where a team applies its high defensive pressure; a high pressing team will disrupt SBS in the opponent’s defensive and mi-third, while a park-the-bus team will focus disrupting the short passes in the opponent’s final third.

The two measures have a high correlation efficiency (r = 0.76), meaning that they describe a similar behavior, i.e. high pressing. Both teams in New York have the highest-pressure defenses in the league. Vancouver, Montreal, and DC. United fared the worst. A surprising finding is that Atlanta United have an average standing in both measures. Most think that they are a high-pressure pressing team. But they may press differently from the teams in New York; Atlanta focus on the counter-pressing and regain the possession as soon as they lose it. But they only maintain the high pressure for a brief period if they can’t retrieve the ball after they lose it.

Both measures also correlate with the xG created/suffered; the higher pressure a team presses, the more opportunities they produce and the fewer chances they suffer.

Data analysis like this can be messy. Normalization and context are essential. Plotting random variables and stats is useless. It wastes everyone’s time. Therefore, comments and collaborations are encouraged to improve the performance of this project

All the data are provided by @AnalysisEvolved.

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